# Sessions

## Create Session

`$ ant beta:sessions create`

**post** `/v1/sessions`

Create Session

### Parameters

- `--agent: string or BetaManagedAgentsAgentParams`

  Body param: Agent identifier. Accepts the `agent` ID string, which pins the latest version for the session, or an `agent` object with both id and version specified.

- `--environment-id: string`

  Body param: ID of the `environment` defining the container configuration for this session.

- `--metadata: optional map[string]`

  Body param: Arbitrary key-value metadata attached to the session. Maximum 16 pairs, keys up to 64 chars, values up to 512 chars.

- `--resource: optional array of BetaManagedAgentsGitHubRepositoryResourceParams or BetaManagedAgentsFileResourceParams or BetaManagedAgentsMemoryStoreResourceParam`

  Body param: Resources (e.g. repositories, files) to mount into the session's container.

- `--title: optional string`

  Body param: Human-readable session title.

- `--vault-id: optional array of string`

  Body param: Vault IDs for stored credentials the agent can use during the session.

- `--beta: optional array of AnthropicBeta`

  Header param: Optional header to specify the beta version(s) you want to use.

### Returns

- `beta_managed_agents_session: object { id, agent, archived_at, 13 more }`

  A Managed Agents `session`.

  - `id: string`

  - `agent: object { id, description, mcp_servers, 8 more }`

    Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time.

    - `id: string`

    - `description: string`

    - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

      - `name: string`

      - `type: "url"`

        - `"url"`

      - `url: string`

    - `model: object { id, speed }`

      Model identifier and configuration.

      - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

        The model that will power your agent.

        See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

        - `"claude-fable-5"`

          Next generation of intelligence for the hardest knowledge work and coding problems

        - `"claude-opus-4-8"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-7"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-6"`

          Most intelligent model for building agents and coding

        - `"claude-sonnet-4-6"`

          Best combination of speed and intelligence

        - `"claude-haiku-4-5"`

          Fastest model with near-frontier intelligence

        - `"claude-haiku-4-5-20251001"`

          Fastest model with near-frontier intelligence

        - `"claude-opus-4-5"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-opus-4-5-20251101"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-sonnet-4-5"`

          High-performance model for agents and coding

        - `"claude-sonnet-4-5-20250929"`

          High-performance model for agents and coding

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `"standard"`

        - `"fast"`

    - `multiagent: object { agents, type }`

      Resolved coordinator topology with full agent definitions for each roster member.

      - `agents: array of BetaManagedAgentsSessionThreadAgent`

        Full `agent` definitions the coordinator may spawn as session threads.

        - `id: string`

        - `description: string`

        - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

          - `name: string`

          - `type: "url"`

          - `url: string`

        - `model: object { id, speed }`

          Model identifier and configuration.

          - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

            The model that will power your agent.

            See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

          - `speed: optional "standard" or "fast"`

            Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `name: string`

        - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

          - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

            A resolved Anthropic-managed skill.

            - `skill_id: string`

            - `type: "anthropic"`

              - `"anthropic"`

            - `version: string`

          - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

            A resolved user-created custom skill.

            - `skill_id: string`

            - `type: "custom"`

              - `"custom"`

            - `version: string`

        - `system: string`

        - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

          - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

            - `configs: array of BetaManagedAgentsAgentToolConfig`

              - `enabled: boolean`

              - `name: "bash" or "edit" or "read" or 5 more`

                Built-in agent tool identifier.

                - `"bash"`

                - `"edit"`

                - `"read"`

                - `"write"`

                - `"glob"`

                - `"grep"`

                - `"web_fetch"`

                - `"web_search"`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                  - `type: "always_allow"`

                    - `"always_allow"`

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

                  - `type: "always_ask"`

                    - `"always_ask"`

            - `default_config: object { enabled, permission_policy }`

              Resolved default configuration for agent tools.

              - `enabled: boolean`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

            - `type: "agent_toolset_20260401"`

              - `"agent_toolset_20260401"`

          - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

            - `configs: array of BetaManagedAgentsMCPToolConfig`

              - `enabled: boolean`

              - `name: string`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

            - `default_config: object { enabled, permission_policy }`

              Resolved default configuration for all tools from an MCP server.

              - `enabled: boolean`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

            - `mcp_server_name: string`

            - `type: "mcp_toolset"`

              - `"mcp_toolset"`

          - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

            A custom tool as returned in API responses.

            - `description: string`

            - `input_schema: object { type, properties, required }`

              JSON Schema for custom tool input parameters.

              - `type: "object"`

              - `properties: optional map[unknown]`

              - `required: optional array of string`

            - `name: string`

            - `type: "custom"`

              - `"custom"`

        - `type: "agent"`

          - `"agent"`

        - `version: number`

      - `type: "coordinator"`

        - `"coordinator"`

    - `name: string`

    - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

      - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

        A resolved Anthropic-managed skill.

      - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

        A resolved user-created custom skill.

    - `system: string`

    - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

      - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

      - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

      - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

        A custom tool as returned in API responses.

    - `type: "agent"`

      - `"agent"`

    - `version: number`

  - `archived_at: string`

    A timestamp in RFC 3339 format

  - `created_at: string`

    A timestamp in RFC 3339 format

  - `environment_id: string`

  - `metadata: map[string]`

  - `outcome_evaluations: array of BetaManagedAgentsOutcomeEvaluationResource`

    Per-outcome evaluation state. One entry per define_outcome event sent to the session.

    - `completed_at: string`

      A timestamp in RFC 3339 format

    - `description: string`

      What the agent should produce.

    - `explanation: string`

      Grader's verdict text from the most recent evaluation. For satisfied, explains why criteria are met; for needs_revision (intermediate), what's missing; for failed, why unrecoverable.

    - `iteration: number`

      0-indexed revision cycle the outcome is currently on.

    - `outcome_id: string`

      Server-generated outc_ ID for this outcome.

    - `result: string`

      Current evaluation state. `pending` before the agent begins work; `running` while producing or revising; `evaluating` while the grader scores; `satisfied`/`max_iterations_reached`/`failed`/`interrupted` are terminal.

    - `type: "outcome_evaluation"`

      - `"outcome_evaluation"`

  - `resources: array of BetaManagedAgentsSessionResource`

    - `beta_managed_agents_github_repository_resource: object { id, created_at, mount_path, 4 more }`

      - `id: string`

      - `created_at: string`

        A timestamp in RFC 3339 format

      - `mount_path: string`

      - `type: "github_repository"`

        - `"github_repository"`

      - `updated_at: string`

        A timestamp in RFC 3339 format

      - `url: string`

      - `checkout: optional BetaManagedAgentsBranchCheckout or BetaManagedAgentsCommitCheckout`

        - `beta_managed_agents_branch_checkout: object { name, type }`

          - `name: string`

            Branch name to check out.

          - `type: "branch"`

            - `"branch"`

        - `beta_managed_agents_commit_checkout: object { sha, type }`

          - `sha: string`

            Full commit SHA to check out.

          - `type: "commit"`

            - `"commit"`

    - `beta_managed_agents_file_resource: object { id, created_at, file_id, 3 more }`

      - `id: string`

      - `created_at: string`

        A timestamp in RFC 3339 format

      - `file_id: string`

      - `mount_path: string`

      - `type: "file"`

        - `"file"`

      - `updated_at: string`

        A timestamp in RFC 3339 format

    - `beta_managed_agents_memory_store_resource: object { memory_store_id, type, access, 4 more }`

      A memory store attached to an agent session.

      - `memory_store_id: string`

        The memory store ID (memstore_...). Must belong to the caller's organization and workspace.

      - `type: "memory_store"`

        - `"memory_store"`

      - `access: optional "read_write" or "read_only"`

        Access mode for an attached memory store.

        - `"read_write"`

        - `"read_only"`

      - `description: optional string`

        Description of the memory store, snapshotted at attach time. Rendered into the agent's system prompt. Empty string when the store has no description.

      - `instructions: optional string`

        Per-attachment guidance for the agent on how to use this store. Rendered into the memory section of the system prompt. Max 4096 chars.

      - `mount_path: optional string`

        Filesystem path where the store is mounted in the session container, e.g. /mnt/memory/user-preferences. Derived from the store's name. Output-only.

      - `name: optional string`

        Display name of the memory store, snapshotted at attach time. Later edits to the store's name do not propagate to this resource.

  - `stats: object { active_seconds, duration_seconds }`

    Timing statistics for a session.

    - `active_seconds: optional number`

      Cumulative time in seconds the session spent in running status. Excludes idle time.

    - `duration_seconds: optional number`

      Elapsed time since session creation in seconds. For terminated sessions, frozen at the final update.

  - `status: "rescheduling" or "running" or "idle" or "terminated"`

    SessionStatus enum

    - `"rescheduling"`

    - `"running"`

    - `"idle"`

    - `"terminated"`

  - `title: string`

  - `type: "session"`

    - `"session"`

  - `updated_at: string`

    A timestamp in RFC 3339 format

  - `usage: object { cache_creation, cache_read_input_tokens, input_tokens, output_tokens }`

    Cumulative token usage for a session across all turns.

    - `cache_creation: optional object { ephemeral_1h_input_tokens, ephemeral_5m_input_tokens }`

      Prompt-cache creation token usage broken down by cache lifetime.

      - `ephemeral_1h_input_tokens: optional number`

        Tokens used to create 1-hour ephemeral cache entries.

      - `ephemeral_5m_input_tokens: optional number`

        Tokens used to create 5-minute ephemeral cache entries.

    - `cache_read_input_tokens: optional number`

      Total tokens read from prompt cache.

    - `input_tokens: optional number`

      Total input tokens consumed across all turns.

    - `output_tokens: optional number`

      Total output tokens generated across all turns.

  - `vault_ids: array of string`

    Vault IDs attached to the session at creation. Empty when no vaults were supplied.

  - `deployment_id: optional string`

    Deployment ID when the session was created from a deployment reference. Null otherwise.

### Example

```cli
ant beta:sessions create \
  --api-key my-anthropic-api-key \
  --agent agent_011CZkYpogX7uDKUyvBTophP \
  --environment-id env_011CZkZ9X2dpNyB7HsEFoRfW
```

#### Response

```json
{
  "id": "sesn_011CZkZAtmR3yMPDzynEDxu7",
  "agent": {
    "id": "agent_011CZkYpogX7uDKUyvBTophP",
    "description": "A general-purpose starter agent.",
    "mcp_servers": [
      {
        "name": "example-mcp",
        "type": "url",
        "url": "https://example-server.modelcontextprotocol.io/sse"
      }
    ],
    "model": {
      "id": "claude-sonnet-4-6",
      "speed": "standard"
    },
    "multiagent": {
      "agents": [
        {
          "id": "agent_011CZkYqphY8vELVzwCUpqiQ",
          "description": "A focused research subagent.",
          "mcp_servers": [
            {
              "name": "example-mcp",
              "type": "url",
              "url": "https://example-server.modelcontextprotocol.io/sse"
            }
          ],
          "model": {
            "id": "claude-sonnet-4-6",
            "speed": "standard"
          },
          "name": "Researcher",
          "skills": [
            {
              "skill_id": "xlsx",
              "type": "anthropic",
              "version": "1"
            }
          ],
          "system": "You are a research subagent that gathers and summarises sources for the coordinating agent.",
          "tools": [
            {
              "configs": [
                {
                  "enabled": true,
                  "name": "bash",
                  "permission_policy": {
                    "type": "always_allow"
                  }
                }
              ],
              "default_config": {
                "enabled": true,
                "permission_policy": {
                  "type": "always_ask"
                }
              },
              "type": "agent_toolset_20260401"
            }
          ],
          "type": "agent",
          "version": 1
        }
      ],
      "type": "coordinator"
    },
    "name": "My First Agent",
    "skills": [
      {
        "skill_id": "xlsx",
        "type": "anthropic",
        "version": "1"
      },
      {
        "skill_id": "skill_011CZkZFNu9hAbo3jZPRgTlx",
        "type": "custom",
        "version": "2"
      }
    ],
    "system": "You are a general-purpose agent that can research, write code, run commands, and use connected tools to complete the user's task end to end.",
    "tools": [
      {
        "configs": [
          {
            "enabled": true,
            "name": "bash",
            "permission_policy": {
              "type": "always_allow"
            }
          }
        ],
        "default_config": {
          "enabled": true,
          "permission_policy": {
            "type": "always_ask"
          }
        },
        "type": "agent_toolset_20260401"
      }
    ],
    "type": "agent",
    "version": 1
  },
  "archived_at": null,
  "created_at": "2026-03-15T10:00:00Z",
  "environment_id": "env_011CZkZ9X2dpNyB7HsEFoRfW",
  "metadata": {},
  "outcome_evaluations": [
    {
      "completed_at": "2026-03-15T10:02:31Z",
      "description": "Produce a 2-page summary as summary.md",
      "explanation": "All five sections present with inline citations.",
      "iteration": 0,
      "outcome_id": "outc_011CZkZRSw2kEfs6ncTVljxP",
      "result": "satisfied",
      "type": "outcome_evaluation"
    }
  ],
  "resources": [
    {
      "id": "sesrsc_011CZkZBJq5dWxk9fVLNcPht",
      "created_at": "2026-03-15T10:00:00Z",
      "file_id": "file_011CNha8iCJcU1wXNR6q4V8w",
      "mount_path": "/uploads/receipt.pdf",
      "type": "file",
      "updated_at": "2026-03-15T10:00:00Z"
    },
    {
      "id": "sesrsc_011CZkZCKr6eXyl0gWMOdQiu",
      "created_at": "2026-03-15T10:00:00Z",
      "mount_path": "/workspace/example-repo",
      "type": "github_repository",
      "updated_at": "2026-03-15T10:00:00Z",
      "url": "https://github.com/example-org/example-repo",
      "checkout": {
        "name": "main",
        "type": "branch"
      }
    }
  ],
  "stats": {
    "active_seconds": 0,
    "duration_seconds": 0
  },
  "status": "idle",
  "title": "Order #1234 inquiry",
  "type": "session",
  "updated_at": "2026-03-15T10:00:00Z",
  "usage": {
    "cache_creation": {
      "ephemeral_1h_input_tokens": 0,
      "ephemeral_5m_input_tokens": 0
    },
    "cache_read_input_tokens": 0,
    "input_tokens": 0,
    "output_tokens": 0
  },
  "vault_ids": [
    "vlt_011CZkZDLs7fYzm1hXNPeRjv"
  ],
  "deployment_id": "deployment_id"
}
```

## List Sessions

`$ ant beta:sessions list`

**get** `/v1/sessions`

List Sessions

### Parameters

- `--agent-id: optional string`

  Query param: Filter sessions created with this agent ID.

- `--agent-version: optional number`

  Query param: Filter by agent version. Only applies when agent_id is also set.

- `--created-at-gt: optional string`

  Query param: Return sessions created after this time (exclusive).

- `--created-at-gte: optional string`

  Query param: Return sessions created at or after this time (inclusive).

- `--created-at-lt: optional string`

  Query param: Return sessions created before this time (exclusive).

- `--created-at-lte: optional string`

  Query param: Return sessions created at or before this time (inclusive).

- `--deployment-id: optional string`

  Query param: Filter sessions created by this deployment ID.

- `--include-archived: optional boolean`

  Query param: When true, includes archived sessions. Default: false (exclude archived).

- `--limit: optional number`

  Query param: Maximum number of results to return.

- `--memory-store-id: optional string`

  Query param: Filter sessions whose resources contain a memory_store with this memory store ID.

- `--order: optional "asc" or "desc"`

  Query param: Sort direction for results, ordered by created_at. Defaults to desc (newest first).

- `--page: optional string`

  Query param: Opaque pagination cursor from a previous response.

- `--status: optional array of "rescheduling" or "running" or "idle" or "terminated"`

  Query param: Filter by session status. Repeat the parameter to match any of multiple statuses.

- `--beta: optional array of AnthropicBeta`

  Header param: Optional header to specify the beta version(s) you want to use.

### Returns

- `BetaManagedAgentsListSessions: object { data, next_page }`

  Paginated list of sessions.

  - `data: optional array of BetaManagedAgentsSession`

    List of sessions.

    - `id: string`

    - `agent: object { id, description, mcp_servers, 8 more }`

      Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time.

      - `id: string`

      - `description: string`

      - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

        - `name: string`

        - `type: "url"`

          - `"url"`

        - `url: string`

      - `model: object { id, speed }`

        Model identifier and configuration.

        - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

          The model that will power your agent.

          See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

          - `"claude-fable-5"`

            Next generation of intelligence for the hardest knowledge work and coding problems

          - `"claude-opus-4-8"`

            Frontier intelligence for long-running agents and coding

          - `"claude-opus-4-7"`

            Frontier intelligence for long-running agents and coding

          - `"claude-opus-4-6"`

            Most intelligent model for building agents and coding

          - `"claude-sonnet-4-6"`

            Best combination of speed and intelligence

          - `"claude-haiku-4-5"`

            Fastest model with near-frontier intelligence

          - `"claude-haiku-4-5-20251001"`

            Fastest model with near-frontier intelligence

          - `"claude-opus-4-5"`

            Premium model combining maximum intelligence with practical performance

          - `"claude-opus-4-5-20251101"`

            Premium model combining maximum intelligence with practical performance

          - `"claude-sonnet-4-5"`

            High-performance model for agents and coding

          - `"claude-sonnet-4-5-20250929"`

            High-performance model for agents and coding

        - `speed: optional "standard" or "fast"`

          Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

          - `"standard"`

          - `"fast"`

      - `multiagent: object { agents, type }`

        Resolved coordinator topology with full agent definitions for each roster member.

        - `agents: array of BetaManagedAgentsSessionThreadAgent`

          Full `agent` definitions the coordinator may spawn as session threads.

          - `id: string`

          - `description: string`

          - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

            - `name: string`

            - `type: "url"`

            - `url: string`

          - `model: object { id, speed }`

            Model identifier and configuration.

            - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

              The model that will power your agent.

              See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

            - `speed: optional "standard" or "fast"`

              Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

          - `name: string`

          - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

            - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

              A resolved Anthropic-managed skill.

              - `skill_id: string`

              - `type: "anthropic"`

                - `"anthropic"`

              - `version: string`

            - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

              A resolved user-created custom skill.

              - `skill_id: string`

              - `type: "custom"`

                - `"custom"`

              - `version: string`

          - `system: string`

          - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

            - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

              - `configs: array of BetaManagedAgentsAgentToolConfig`

                - `enabled: boolean`

                - `name: "bash" or "edit" or "read" or 5 more`

                  Built-in agent tool identifier.

                  - `"bash"`

                  - `"edit"`

                  - `"read"`

                  - `"write"`

                  - `"glob"`

                  - `"grep"`

                  - `"web_fetch"`

                  - `"web_search"`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                    - `type: "always_allow"`

                      - `"always_allow"`

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

                    - `type: "always_ask"`

                      - `"always_ask"`

              - `default_config: object { enabled, permission_policy }`

                Resolved default configuration for agent tools.

                - `enabled: boolean`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

              - `type: "agent_toolset_20260401"`

                - `"agent_toolset_20260401"`

            - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

              - `configs: array of BetaManagedAgentsMCPToolConfig`

                - `enabled: boolean`

                - `name: string`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

              - `default_config: object { enabled, permission_policy }`

                Resolved default configuration for all tools from an MCP server.

                - `enabled: boolean`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

              - `mcp_server_name: string`

              - `type: "mcp_toolset"`

                - `"mcp_toolset"`

            - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

              A custom tool as returned in API responses.

              - `description: string`

              - `input_schema: object { type, properties, required }`

                JSON Schema for custom tool input parameters.

                - `type: "object"`

                - `properties: optional map[unknown]`

                - `required: optional array of string`

              - `name: string`

              - `type: "custom"`

                - `"custom"`

          - `type: "agent"`

            - `"agent"`

          - `version: number`

        - `type: "coordinator"`

          - `"coordinator"`

      - `name: string`

      - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

        - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

          A resolved Anthropic-managed skill.

        - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

          A resolved user-created custom skill.

      - `system: string`

      - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

        - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

        - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

        - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

          A custom tool as returned in API responses.

      - `type: "agent"`

        - `"agent"`

      - `version: number`

    - `archived_at: string`

      A timestamp in RFC 3339 format

    - `created_at: string`

      A timestamp in RFC 3339 format

    - `environment_id: string`

    - `metadata: map[string]`

    - `outcome_evaluations: array of BetaManagedAgentsOutcomeEvaluationResource`

      Per-outcome evaluation state. One entry per define_outcome event sent to the session.

      - `completed_at: string`

        A timestamp in RFC 3339 format

      - `description: string`

        What the agent should produce.

      - `explanation: string`

        Grader's verdict text from the most recent evaluation. For satisfied, explains why criteria are met; for needs_revision (intermediate), what's missing; for failed, why unrecoverable.

      - `iteration: number`

        0-indexed revision cycle the outcome is currently on.

      - `outcome_id: string`

        Server-generated outc_ ID for this outcome.

      - `result: string`

        Current evaluation state. `pending` before the agent begins work; `running` while producing or revising; `evaluating` while the grader scores; `satisfied`/`max_iterations_reached`/`failed`/`interrupted` are terminal.

      - `type: "outcome_evaluation"`

        - `"outcome_evaluation"`

    - `resources: array of BetaManagedAgentsSessionResource`

      - `beta_managed_agents_github_repository_resource: object { id, created_at, mount_path, 4 more }`

        - `id: string`

        - `created_at: string`

          A timestamp in RFC 3339 format

        - `mount_path: string`

        - `type: "github_repository"`

          - `"github_repository"`

        - `updated_at: string`

          A timestamp in RFC 3339 format

        - `url: string`

        - `checkout: optional BetaManagedAgentsBranchCheckout or BetaManagedAgentsCommitCheckout`

          - `beta_managed_agents_branch_checkout: object { name, type }`

            - `name: string`

              Branch name to check out.

            - `type: "branch"`

              - `"branch"`

          - `beta_managed_agents_commit_checkout: object { sha, type }`

            - `sha: string`

              Full commit SHA to check out.

            - `type: "commit"`

              - `"commit"`

      - `beta_managed_agents_file_resource: object { id, created_at, file_id, 3 more }`

        - `id: string`

        - `created_at: string`

          A timestamp in RFC 3339 format

        - `file_id: string`

        - `mount_path: string`

        - `type: "file"`

          - `"file"`

        - `updated_at: string`

          A timestamp in RFC 3339 format

      - `beta_managed_agents_memory_store_resource: object { memory_store_id, type, access, 4 more }`

        A memory store attached to an agent session.

        - `memory_store_id: string`

          The memory store ID (memstore_...). Must belong to the caller's organization and workspace.

        - `type: "memory_store"`

          - `"memory_store"`

        - `access: optional "read_write" or "read_only"`

          Access mode for an attached memory store.

          - `"read_write"`

          - `"read_only"`

        - `description: optional string`

          Description of the memory store, snapshotted at attach time. Rendered into the agent's system prompt. Empty string when the store has no description.

        - `instructions: optional string`

          Per-attachment guidance for the agent on how to use this store. Rendered into the memory section of the system prompt. Max 4096 chars.

        - `mount_path: optional string`

          Filesystem path where the store is mounted in the session container, e.g. /mnt/memory/user-preferences. Derived from the store's name. Output-only.

        - `name: optional string`

          Display name of the memory store, snapshotted at attach time. Later edits to the store's name do not propagate to this resource.

    - `stats: object { active_seconds, duration_seconds }`

      Timing statistics for a session.

      - `active_seconds: optional number`

        Cumulative time in seconds the session spent in running status. Excludes idle time.

      - `duration_seconds: optional number`

        Elapsed time since session creation in seconds. For terminated sessions, frozen at the final update.

    - `status: "rescheduling" or "running" or "idle" or "terminated"`

      SessionStatus enum

      - `"rescheduling"`

      - `"running"`

      - `"idle"`

      - `"terminated"`

    - `title: string`

    - `type: "session"`

      - `"session"`

    - `updated_at: string`

      A timestamp in RFC 3339 format

    - `usage: object { cache_creation, cache_read_input_tokens, input_tokens, output_tokens }`

      Cumulative token usage for a session across all turns.

      - `cache_creation: optional object { ephemeral_1h_input_tokens, ephemeral_5m_input_tokens }`

        Prompt-cache creation token usage broken down by cache lifetime.

        - `ephemeral_1h_input_tokens: optional number`

          Tokens used to create 1-hour ephemeral cache entries.

        - `ephemeral_5m_input_tokens: optional number`

          Tokens used to create 5-minute ephemeral cache entries.

      - `cache_read_input_tokens: optional number`

        Total tokens read from prompt cache.

      - `input_tokens: optional number`

        Total input tokens consumed across all turns.

      - `output_tokens: optional number`

        Total output tokens generated across all turns.

    - `vault_ids: array of string`

      Vault IDs attached to the session at creation. Empty when no vaults were supplied.

    - `deployment_id: optional string`

      Deployment ID when the session was created from a deployment reference. Null otherwise.

  - `next_page: optional string`

    Opaque cursor for the next page. Null when no more results.

### Example

```cli
ant beta:sessions list \
  --api-key my-anthropic-api-key
```

#### Response

```json
{
  "data": [
    {
      "id": "sesn_011CZkZAtmR3yMPDzynEDxu7",
      "agent": {
        "id": "agent_011CZkYpogX7uDKUyvBTophP",
        "description": "A general-purpose starter agent.",
        "mcp_servers": [
          {
            "name": "example-mcp",
            "type": "url",
            "url": "https://example-server.modelcontextprotocol.io/sse"
          }
        ],
        "model": {
          "id": "claude-sonnet-4-6",
          "speed": "standard"
        },
        "multiagent": {
          "agents": [
            {
              "id": "agent_011CZkYqphY8vELVzwCUpqiQ",
              "description": "A focused research subagent.",
              "mcp_servers": [
                {
                  "name": "example-mcp",
                  "type": "url",
                  "url": "https://example-server.modelcontextprotocol.io/sse"
                }
              ],
              "model": {
                "id": "claude-sonnet-4-6",
                "speed": "standard"
              },
              "name": "Researcher",
              "skills": [
                {
                  "skill_id": "xlsx",
                  "type": "anthropic",
                  "version": "1"
                }
              ],
              "system": "You are a research subagent that gathers and summarises sources for the coordinating agent.",
              "tools": [
                {
                  "configs": [
                    {
                      "enabled": true,
                      "name": "bash",
                      "permission_policy": {
                        "type": "always_allow"
                      }
                    }
                  ],
                  "default_config": {
                    "enabled": true,
                    "permission_policy": {
                      "type": "always_ask"
                    }
                  },
                  "type": "agent_toolset_20260401"
                }
              ],
              "type": "agent",
              "version": 1
            }
          ],
          "type": "coordinator"
        },
        "name": "My First Agent",
        "skills": [
          {
            "skill_id": "xlsx",
            "type": "anthropic",
            "version": "1"
          },
          {
            "skill_id": "skill_011CZkZFNu9hAbo3jZPRgTlx",
            "type": "custom",
            "version": "2"
          }
        ],
        "system": "You are a general-purpose agent that can research, write code, run commands, and use connected tools to complete the user's task end to end.",
        "tools": [
          {
            "configs": [
              {
                "enabled": true,
                "name": "bash",
                "permission_policy": {
                  "type": "always_allow"
                }
              }
            ],
            "default_config": {
              "enabled": true,
              "permission_policy": {
                "type": "always_ask"
              }
            },
            "type": "agent_toolset_20260401"
          }
        ],
        "type": "agent",
        "version": 1
      },
      "archived_at": null,
      "created_at": "2026-03-15T10:00:00Z",
      "environment_id": "env_011CZkZ9X2dpNyB7HsEFoRfW",
      "metadata": {},
      "outcome_evaluations": [
        {
          "completed_at": "2026-03-15T10:02:31Z",
          "description": "Produce a 2-page summary as summary.md",
          "explanation": "All five sections present with inline citations.",
          "iteration": 0,
          "outcome_id": "outc_011CZkZRSw2kEfs6ncTVljxP",
          "result": "satisfied",
          "type": "outcome_evaluation"
        }
      ],
      "resources": [
        {
          "id": "sesrsc_011CZkZBJq5dWxk9fVLNcPht",
          "created_at": "2026-03-15T10:00:00Z",
          "file_id": "file_011CNha8iCJcU1wXNR6q4V8w",
          "mount_path": "/uploads/receipt.pdf",
          "type": "file",
          "updated_at": "2026-03-15T10:00:00Z"
        },
        {
          "id": "sesrsc_011CZkZCKr6eXyl0gWMOdQiu",
          "created_at": "2026-03-15T10:00:00Z",
          "mount_path": "/workspace/example-repo",
          "type": "github_repository",
          "updated_at": "2026-03-15T10:00:00Z",
          "url": "https://github.com/example-org/example-repo",
          "checkout": {
            "name": "main",
            "type": "branch"
          }
        }
      ],
      "stats": {
        "active_seconds": 0,
        "duration_seconds": 0
      },
      "status": "idle",
      "title": "Order #1234 inquiry",
      "type": "session",
      "updated_at": "2026-03-15T10:00:00Z",
      "usage": {
        "cache_creation": {
          "ephemeral_1h_input_tokens": 0,
          "ephemeral_5m_input_tokens": 0
        },
        "cache_read_input_tokens": 0,
        "input_tokens": 0,
        "output_tokens": 0
      },
      "vault_ids": [
        "vlt_011CZkZDLs7fYzm1hXNPeRjv"
      ],
      "deployment_id": "deployment_id"
    }
  ],
  "next_page": "page_MjAyNS0wNS0xNFQwMDowMDowMFo="
}
```

## Get Session

`$ ant beta:sessions retrieve`

**get** `/v1/sessions/{session_id}`

Get Session

### Parameters

- `--session-id: string`

  Path parameter session_id

- `--beta: optional array of AnthropicBeta`

  Optional header to specify the beta version(s) you want to use.

### Returns

- `beta_managed_agents_session: object { id, agent, archived_at, 13 more }`

  A Managed Agents `session`.

  - `id: string`

  - `agent: object { id, description, mcp_servers, 8 more }`

    Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time.

    - `id: string`

    - `description: string`

    - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

      - `name: string`

      - `type: "url"`

        - `"url"`

      - `url: string`

    - `model: object { id, speed }`

      Model identifier and configuration.

      - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

        The model that will power your agent.

        See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

        - `"claude-fable-5"`

          Next generation of intelligence for the hardest knowledge work and coding problems

        - `"claude-opus-4-8"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-7"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-6"`

          Most intelligent model for building agents and coding

        - `"claude-sonnet-4-6"`

          Best combination of speed and intelligence

        - `"claude-haiku-4-5"`

          Fastest model with near-frontier intelligence

        - `"claude-haiku-4-5-20251001"`

          Fastest model with near-frontier intelligence

        - `"claude-opus-4-5"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-opus-4-5-20251101"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-sonnet-4-5"`

          High-performance model for agents and coding

        - `"claude-sonnet-4-5-20250929"`

          High-performance model for agents and coding

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `"standard"`

        - `"fast"`

    - `multiagent: object { agents, type }`

      Resolved coordinator topology with full agent definitions for each roster member.

      - `agents: array of BetaManagedAgentsSessionThreadAgent`

        Full `agent` definitions the coordinator may spawn as session threads.

        - `id: string`

        - `description: string`

        - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

          - `name: string`

          - `type: "url"`

          - `url: string`

        - `model: object { id, speed }`

          Model identifier and configuration.

          - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

            The model that will power your agent.

            See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

          - `speed: optional "standard" or "fast"`

            Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `name: string`

        - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

          - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

            A resolved Anthropic-managed skill.

            - `skill_id: string`

            - `type: "anthropic"`

              - `"anthropic"`

            - `version: string`

          - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

            A resolved user-created custom skill.

            - `skill_id: string`

            - `type: "custom"`

              - `"custom"`

            - `version: string`

        - `system: string`

        - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

          - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

            - `configs: array of BetaManagedAgentsAgentToolConfig`

              - `enabled: boolean`

              - `name: "bash" or "edit" or "read" or 5 more`

                Built-in agent tool identifier.

                - `"bash"`

                - `"edit"`

                - `"read"`

                - `"write"`

                - `"glob"`

                - `"grep"`

                - `"web_fetch"`

                - `"web_search"`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                  - `type: "always_allow"`

                    - `"always_allow"`

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

                  - `type: "always_ask"`

                    - `"always_ask"`

            - `default_config: object { enabled, permission_policy }`

              Resolved default configuration for agent tools.

              - `enabled: boolean`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

            - `type: "agent_toolset_20260401"`

              - `"agent_toolset_20260401"`

          - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

            - `configs: array of BetaManagedAgentsMCPToolConfig`

              - `enabled: boolean`

              - `name: string`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

            - `default_config: object { enabled, permission_policy }`

              Resolved default configuration for all tools from an MCP server.

              - `enabled: boolean`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

            - `mcp_server_name: string`

            - `type: "mcp_toolset"`

              - `"mcp_toolset"`

          - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

            A custom tool as returned in API responses.

            - `description: string`

            - `input_schema: object { type, properties, required }`

              JSON Schema for custom tool input parameters.

              - `type: "object"`

              - `properties: optional map[unknown]`

              - `required: optional array of string`

            - `name: string`

            - `type: "custom"`

              - `"custom"`

        - `type: "agent"`

          - `"agent"`

        - `version: number`

      - `type: "coordinator"`

        - `"coordinator"`

    - `name: string`

    - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

      - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

        A resolved Anthropic-managed skill.

      - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

        A resolved user-created custom skill.

    - `system: string`

    - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

      - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

      - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

      - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

        A custom tool as returned in API responses.

    - `type: "agent"`

      - `"agent"`

    - `version: number`

  - `archived_at: string`

    A timestamp in RFC 3339 format

  - `created_at: string`

    A timestamp in RFC 3339 format

  - `environment_id: string`

  - `metadata: map[string]`

  - `outcome_evaluations: array of BetaManagedAgentsOutcomeEvaluationResource`

    Per-outcome evaluation state. One entry per define_outcome event sent to the session.

    - `completed_at: string`

      A timestamp in RFC 3339 format

    - `description: string`

      What the agent should produce.

    - `explanation: string`

      Grader's verdict text from the most recent evaluation. For satisfied, explains why criteria are met; for needs_revision (intermediate), what's missing; for failed, why unrecoverable.

    - `iteration: number`

      0-indexed revision cycle the outcome is currently on.

    - `outcome_id: string`

      Server-generated outc_ ID for this outcome.

    - `result: string`

      Current evaluation state. `pending` before the agent begins work; `running` while producing or revising; `evaluating` while the grader scores; `satisfied`/`max_iterations_reached`/`failed`/`interrupted` are terminal.

    - `type: "outcome_evaluation"`

      - `"outcome_evaluation"`

  - `resources: array of BetaManagedAgentsSessionResource`

    - `beta_managed_agents_github_repository_resource: object { id, created_at, mount_path, 4 more }`

      - `id: string`

      - `created_at: string`

        A timestamp in RFC 3339 format

      - `mount_path: string`

      - `type: "github_repository"`

        - `"github_repository"`

      - `updated_at: string`

        A timestamp in RFC 3339 format

      - `url: string`

      - `checkout: optional BetaManagedAgentsBranchCheckout or BetaManagedAgentsCommitCheckout`

        - `beta_managed_agents_branch_checkout: object { name, type }`

          - `name: string`

            Branch name to check out.

          - `type: "branch"`

            - `"branch"`

        - `beta_managed_agents_commit_checkout: object { sha, type }`

          - `sha: string`

            Full commit SHA to check out.

          - `type: "commit"`

            - `"commit"`

    - `beta_managed_agents_file_resource: object { id, created_at, file_id, 3 more }`

      - `id: string`

      - `created_at: string`

        A timestamp in RFC 3339 format

      - `file_id: string`

      - `mount_path: string`

      - `type: "file"`

        - `"file"`

      - `updated_at: string`

        A timestamp in RFC 3339 format

    - `beta_managed_agents_memory_store_resource: object { memory_store_id, type, access, 4 more }`

      A memory store attached to an agent session.

      - `memory_store_id: string`

        The memory store ID (memstore_...). Must belong to the caller's organization and workspace.

      - `type: "memory_store"`

        - `"memory_store"`

      - `access: optional "read_write" or "read_only"`

        Access mode for an attached memory store.

        - `"read_write"`

        - `"read_only"`

      - `description: optional string`

        Description of the memory store, snapshotted at attach time. Rendered into the agent's system prompt. Empty string when the store has no description.

      - `instructions: optional string`

        Per-attachment guidance for the agent on how to use this store. Rendered into the memory section of the system prompt. Max 4096 chars.

      - `mount_path: optional string`

        Filesystem path where the store is mounted in the session container, e.g. /mnt/memory/user-preferences. Derived from the store's name. Output-only.

      - `name: optional string`

        Display name of the memory store, snapshotted at attach time. Later edits to the store's name do not propagate to this resource.

  - `stats: object { active_seconds, duration_seconds }`

    Timing statistics for a session.

    - `active_seconds: optional number`

      Cumulative time in seconds the session spent in running status. Excludes idle time.

    - `duration_seconds: optional number`

      Elapsed time since session creation in seconds. For terminated sessions, frozen at the final update.

  - `status: "rescheduling" or "running" or "idle" or "terminated"`

    SessionStatus enum

    - `"rescheduling"`

    - `"running"`

    - `"idle"`

    - `"terminated"`

  - `title: string`

  - `type: "session"`

    - `"session"`

  - `updated_at: string`

    A timestamp in RFC 3339 format

  - `usage: object { cache_creation, cache_read_input_tokens, input_tokens, output_tokens }`

    Cumulative token usage for a session across all turns.

    - `cache_creation: optional object { ephemeral_1h_input_tokens, ephemeral_5m_input_tokens }`

      Prompt-cache creation token usage broken down by cache lifetime.

      - `ephemeral_1h_input_tokens: optional number`

        Tokens used to create 1-hour ephemeral cache entries.

      - `ephemeral_5m_input_tokens: optional number`

        Tokens used to create 5-minute ephemeral cache entries.

    - `cache_read_input_tokens: optional number`

      Total tokens read from prompt cache.

    - `input_tokens: optional number`

      Total input tokens consumed across all turns.

    - `output_tokens: optional number`

      Total output tokens generated across all turns.

  - `vault_ids: array of string`

    Vault IDs attached to the session at creation. Empty when no vaults were supplied.

  - `deployment_id: optional string`

    Deployment ID when the session was created from a deployment reference. Null otherwise.

### Example

```cli
ant beta:sessions retrieve \
  --api-key my-anthropic-api-key \
  --session-id sesn_011CZkZAtmR3yMPDzynEDxu7
```

#### Response

```json
{
  "id": "sesn_011CZkZAtmR3yMPDzynEDxu7",
  "agent": {
    "id": "agent_011CZkYpogX7uDKUyvBTophP",
    "description": "A general-purpose starter agent.",
    "mcp_servers": [
      {
        "name": "example-mcp",
        "type": "url",
        "url": "https://example-server.modelcontextprotocol.io/sse"
      }
    ],
    "model": {
      "id": "claude-sonnet-4-6",
      "speed": "standard"
    },
    "multiagent": {
      "agents": [
        {
          "id": "agent_011CZkYqphY8vELVzwCUpqiQ",
          "description": "A focused research subagent.",
          "mcp_servers": [
            {
              "name": "example-mcp",
              "type": "url",
              "url": "https://example-server.modelcontextprotocol.io/sse"
            }
          ],
          "model": {
            "id": "claude-sonnet-4-6",
            "speed": "standard"
          },
          "name": "Researcher",
          "skills": [
            {
              "skill_id": "xlsx",
              "type": "anthropic",
              "version": "1"
            }
          ],
          "system": "You are a research subagent that gathers and summarises sources for the coordinating agent.",
          "tools": [
            {
              "configs": [
                {
                  "enabled": true,
                  "name": "bash",
                  "permission_policy": {
                    "type": "always_allow"
                  }
                }
              ],
              "default_config": {
                "enabled": true,
                "permission_policy": {
                  "type": "always_ask"
                }
              },
              "type": "agent_toolset_20260401"
            }
          ],
          "type": "agent",
          "version": 1
        }
      ],
      "type": "coordinator"
    },
    "name": "My First Agent",
    "skills": [
      {
        "skill_id": "xlsx",
        "type": "anthropic",
        "version": "1"
      },
      {
        "skill_id": "skill_011CZkZFNu9hAbo3jZPRgTlx",
        "type": "custom",
        "version": "2"
      }
    ],
    "system": "You are a general-purpose agent that can research, write code, run commands, and use connected tools to complete the user's task end to end.",
    "tools": [
      {
        "configs": [
          {
            "enabled": true,
            "name": "bash",
            "permission_policy": {
              "type": "always_allow"
            }
          }
        ],
        "default_config": {
          "enabled": true,
          "permission_policy": {
            "type": "always_ask"
          }
        },
        "type": "agent_toolset_20260401"
      }
    ],
    "type": "agent",
    "version": 1
  },
  "archived_at": null,
  "created_at": "2026-03-15T10:00:00Z",
  "environment_id": "env_011CZkZ9X2dpNyB7HsEFoRfW",
  "metadata": {},
  "outcome_evaluations": [
    {
      "completed_at": "2026-03-15T10:02:31Z",
      "description": "Produce a 2-page summary as summary.md",
      "explanation": "All five sections present with inline citations.",
      "iteration": 0,
      "outcome_id": "outc_011CZkZRSw2kEfs6ncTVljxP",
      "result": "satisfied",
      "type": "outcome_evaluation"
    }
  ],
  "resources": [
    {
      "id": "sesrsc_011CZkZBJq5dWxk9fVLNcPht",
      "created_at": "2026-03-15T10:00:00Z",
      "file_id": "file_011CNha8iCJcU1wXNR6q4V8w",
      "mount_path": "/uploads/receipt.pdf",
      "type": "file",
      "updated_at": "2026-03-15T10:00:00Z"
    },
    {
      "id": "sesrsc_011CZkZCKr6eXyl0gWMOdQiu",
      "created_at": "2026-03-15T10:00:00Z",
      "mount_path": "/workspace/example-repo",
      "type": "github_repository",
      "updated_at": "2026-03-15T10:00:00Z",
      "url": "https://github.com/example-org/example-repo",
      "checkout": {
        "name": "main",
        "type": "branch"
      }
    }
  ],
  "stats": {
    "active_seconds": 0,
    "duration_seconds": 0
  },
  "status": "idle",
  "title": "Order #1234 inquiry",
  "type": "session",
  "updated_at": "2026-03-15T10:00:00Z",
  "usage": {
    "cache_creation": {
      "ephemeral_1h_input_tokens": 0,
      "ephemeral_5m_input_tokens": 0
    },
    "cache_read_input_tokens": 0,
    "input_tokens": 0,
    "output_tokens": 0
  },
  "vault_ids": [
    "vlt_011CZkZDLs7fYzm1hXNPeRjv"
  ],
  "deployment_id": "deployment_id"
}
```

## Update Session

`$ ant beta:sessions update`

**post** `/v1/sessions/{session_id}`

Update Session

### Parameters

- `--session-id: string`

  Path param: Path parameter session_id

- `--agent: optional object { mcp_servers, tools }`

  Body param: Mid-session agent configuration update. Only `tools` and `mcp_servers` are updatable. Full replacement: the provided array becomes the new value. To preserve existing entries, GET the session, modify the array, and POST it back.

- `--metadata: optional map[string]`

  Body param: Metadata patch. Set a key to a string to upsert it, or to null to delete it. Omit the field to preserve.

- `--title: optional string`

  Body param: Human-readable session title.

- `--vault-id: optional array of string`

  Body param: Vault IDs (`vlt_*`) to attach to the session. Not yet supported; requests setting this field are rejected. Reserved for future use.

- `--beta: optional array of AnthropicBeta`

  Header param: Optional header to specify the beta version(s) you want to use.

### Returns

- `beta_managed_agents_session: object { id, agent, archived_at, 13 more }`

  A Managed Agents `session`.

  - `id: string`

  - `agent: object { id, description, mcp_servers, 8 more }`

    Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time.

    - `id: string`

    - `description: string`

    - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

      - `name: string`

      - `type: "url"`

        - `"url"`

      - `url: string`

    - `model: object { id, speed }`

      Model identifier and configuration.

      - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

        The model that will power your agent.

        See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

        - `"claude-fable-5"`

          Next generation of intelligence for the hardest knowledge work and coding problems

        - `"claude-opus-4-8"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-7"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-6"`

          Most intelligent model for building agents and coding

        - `"claude-sonnet-4-6"`

          Best combination of speed and intelligence

        - `"claude-haiku-4-5"`

          Fastest model with near-frontier intelligence

        - `"claude-haiku-4-5-20251001"`

          Fastest model with near-frontier intelligence

        - `"claude-opus-4-5"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-opus-4-5-20251101"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-sonnet-4-5"`

          High-performance model for agents and coding

        - `"claude-sonnet-4-5-20250929"`

          High-performance model for agents and coding

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `"standard"`

        - `"fast"`

    - `multiagent: object { agents, type }`

      Resolved coordinator topology with full agent definitions for each roster member.

      - `agents: array of BetaManagedAgentsSessionThreadAgent`

        Full `agent` definitions the coordinator may spawn as session threads.

        - `id: string`

        - `description: string`

        - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

          - `name: string`

          - `type: "url"`

          - `url: string`

        - `model: object { id, speed }`

          Model identifier and configuration.

          - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

            The model that will power your agent.

            See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

          - `speed: optional "standard" or "fast"`

            Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `name: string`

        - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

          - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

            A resolved Anthropic-managed skill.

            - `skill_id: string`

            - `type: "anthropic"`

              - `"anthropic"`

            - `version: string`

          - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

            A resolved user-created custom skill.

            - `skill_id: string`

            - `type: "custom"`

              - `"custom"`

            - `version: string`

        - `system: string`

        - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

          - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

            - `configs: array of BetaManagedAgentsAgentToolConfig`

              - `enabled: boolean`

              - `name: "bash" or "edit" or "read" or 5 more`

                Built-in agent tool identifier.

                - `"bash"`

                - `"edit"`

                - `"read"`

                - `"write"`

                - `"glob"`

                - `"grep"`

                - `"web_fetch"`

                - `"web_search"`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                  - `type: "always_allow"`

                    - `"always_allow"`

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

                  - `type: "always_ask"`

                    - `"always_ask"`

            - `default_config: object { enabled, permission_policy }`

              Resolved default configuration for agent tools.

              - `enabled: boolean`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

            - `type: "agent_toolset_20260401"`

              - `"agent_toolset_20260401"`

          - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

            - `configs: array of BetaManagedAgentsMCPToolConfig`

              - `enabled: boolean`

              - `name: string`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

            - `default_config: object { enabled, permission_policy }`

              Resolved default configuration for all tools from an MCP server.

              - `enabled: boolean`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

            - `mcp_server_name: string`

            - `type: "mcp_toolset"`

              - `"mcp_toolset"`

          - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

            A custom tool as returned in API responses.

            - `description: string`

            - `input_schema: object { type, properties, required }`

              JSON Schema for custom tool input parameters.

              - `type: "object"`

              - `properties: optional map[unknown]`

              - `required: optional array of string`

            - `name: string`

            - `type: "custom"`

              - `"custom"`

        - `type: "agent"`

          - `"agent"`

        - `version: number`

      - `type: "coordinator"`

        - `"coordinator"`

    - `name: string`

    - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

      - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

        A resolved Anthropic-managed skill.

      - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

        A resolved user-created custom skill.

    - `system: string`

    - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

      - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

      - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

      - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

        A custom tool as returned in API responses.

    - `type: "agent"`

      - `"agent"`

    - `version: number`

  - `archived_at: string`

    A timestamp in RFC 3339 format

  - `created_at: string`

    A timestamp in RFC 3339 format

  - `environment_id: string`

  - `metadata: map[string]`

  - `outcome_evaluations: array of BetaManagedAgentsOutcomeEvaluationResource`

    Per-outcome evaluation state. One entry per define_outcome event sent to the session.

    - `completed_at: string`

      A timestamp in RFC 3339 format

    - `description: string`

      What the agent should produce.

    - `explanation: string`

      Grader's verdict text from the most recent evaluation. For satisfied, explains why criteria are met; for needs_revision (intermediate), what's missing; for failed, why unrecoverable.

    - `iteration: number`

      0-indexed revision cycle the outcome is currently on.

    - `outcome_id: string`

      Server-generated outc_ ID for this outcome.

    - `result: string`

      Current evaluation state. `pending` before the agent begins work; `running` while producing or revising; `evaluating` while the grader scores; `satisfied`/`max_iterations_reached`/`failed`/`interrupted` are terminal.

    - `type: "outcome_evaluation"`

      - `"outcome_evaluation"`

  - `resources: array of BetaManagedAgentsSessionResource`

    - `beta_managed_agents_github_repository_resource: object { id, created_at, mount_path, 4 more }`

      - `id: string`

      - `created_at: string`

        A timestamp in RFC 3339 format

      - `mount_path: string`

      - `type: "github_repository"`

        - `"github_repository"`

      - `updated_at: string`

        A timestamp in RFC 3339 format

      - `url: string`

      - `checkout: optional BetaManagedAgentsBranchCheckout or BetaManagedAgentsCommitCheckout`

        - `beta_managed_agents_branch_checkout: object { name, type }`

          - `name: string`

            Branch name to check out.

          - `type: "branch"`

            - `"branch"`

        - `beta_managed_agents_commit_checkout: object { sha, type }`

          - `sha: string`

            Full commit SHA to check out.

          - `type: "commit"`

            - `"commit"`

    - `beta_managed_agents_file_resource: object { id, created_at, file_id, 3 more }`

      - `id: string`

      - `created_at: string`

        A timestamp in RFC 3339 format

      - `file_id: string`

      - `mount_path: string`

      - `type: "file"`

        - `"file"`

      - `updated_at: string`

        A timestamp in RFC 3339 format

    - `beta_managed_agents_memory_store_resource: object { memory_store_id, type, access, 4 more }`

      A memory store attached to an agent session.

      - `memory_store_id: string`

        The memory store ID (memstore_...). Must belong to the caller's organization and workspace.

      - `type: "memory_store"`

        - `"memory_store"`

      - `access: optional "read_write" or "read_only"`

        Access mode for an attached memory store.

        - `"read_write"`

        - `"read_only"`

      - `description: optional string`

        Description of the memory store, snapshotted at attach time. Rendered into the agent's system prompt. Empty string when the store has no description.

      - `instructions: optional string`

        Per-attachment guidance for the agent on how to use this store. Rendered into the memory section of the system prompt. Max 4096 chars.

      - `mount_path: optional string`

        Filesystem path where the store is mounted in the session container, e.g. /mnt/memory/user-preferences. Derived from the store's name. Output-only.

      - `name: optional string`

        Display name of the memory store, snapshotted at attach time. Later edits to the store's name do not propagate to this resource.

  - `stats: object { active_seconds, duration_seconds }`

    Timing statistics for a session.

    - `active_seconds: optional number`

      Cumulative time in seconds the session spent in running status. Excludes idle time.

    - `duration_seconds: optional number`

      Elapsed time since session creation in seconds. For terminated sessions, frozen at the final update.

  - `status: "rescheduling" or "running" or "idle" or "terminated"`

    SessionStatus enum

    - `"rescheduling"`

    - `"running"`

    - `"idle"`

    - `"terminated"`

  - `title: string`

  - `type: "session"`

    - `"session"`

  - `updated_at: string`

    A timestamp in RFC 3339 format

  - `usage: object { cache_creation, cache_read_input_tokens, input_tokens, output_tokens }`

    Cumulative token usage for a session across all turns.

    - `cache_creation: optional object { ephemeral_1h_input_tokens, ephemeral_5m_input_tokens }`

      Prompt-cache creation token usage broken down by cache lifetime.

      - `ephemeral_1h_input_tokens: optional number`

        Tokens used to create 1-hour ephemeral cache entries.

      - `ephemeral_5m_input_tokens: optional number`

        Tokens used to create 5-minute ephemeral cache entries.

    - `cache_read_input_tokens: optional number`

      Total tokens read from prompt cache.

    - `input_tokens: optional number`

      Total input tokens consumed across all turns.

    - `output_tokens: optional number`

      Total output tokens generated across all turns.

  - `vault_ids: array of string`

    Vault IDs attached to the session at creation. Empty when no vaults were supplied.

  - `deployment_id: optional string`

    Deployment ID when the session was created from a deployment reference. Null otherwise.

### Example

```cli
ant beta:sessions update \
  --api-key my-anthropic-api-key \
  --session-id sesn_011CZkZAtmR3yMPDzynEDxu7
```

#### Response

```json
{
  "id": "sesn_011CZkZAtmR3yMPDzynEDxu7",
  "agent": {
    "id": "agent_011CZkYpogX7uDKUyvBTophP",
    "description": "A general-purpose starter agent.",
    "mcp_servers": [
      {
        "name": "example-mcp",
        "type": "url",
        "url": "https://example-server.modelcontextprotocol.io/sse"
      }
    ],
    "model": {
      "id": "claude-sonnet-4-6",
      "speed": "standard"
    },
    "multiagent": {
      "agents": [
        {
          "id": "agent_011CZkYqphY8vELVzwCUpqiQ",
          "description": "A focused research subagent.",
          "mcp_servers": [
            {
              "name": "example-mcp",
              "type": "url",
              "url": "https://example-server.modelcontextprotocol.io/sse"
            }
          ],
          "model": {
            "id": "claude-sonnet-4-6",
            "speed": "standard"
          },
          "name": "Researcher",
          "skills": [
            {
              "skill_id": "xlsx",
              "type": "anthropic",
              "version": "1"
            }
          ],
          "system": "You are a research subagent that gathers and summarises sources for the coordinating agent.",
          "tools": [
            {
              "configs": [
                {
                  "enabled": true,
                  "name": "bash",
                  "permission_policy": {
                    "type": "always_allow"
                  }
                }
              ],
              "default_config": {
                "enabled": true,
                "permission_policy": {
                  "type": "always_ask"
                }
              },
              "type": "agent_toolset_20260401"
            }
          ],
          "type": "agent",
          "version": 1
        }
      ],
      "type": "coordinator"
    },
    "name": "My First Agent",
    "skills": [
      {
        "skill_id": "xlsx",
        "type": "anthropic",
        "version": "1"
      },
      {
        "skill_id": "skill_011CZkZFNu9hAbo3jZPRgTlx",
        "type": "custom",
        "version": "2"
      }
    ],
    "system": "You are a general-purpose agent that can research, write code, run commands, and use connected tools to complete the user's task end to end.",
    "tools": [
      {
        "configs": [
          {
            "enabled": true,
            "name": "bash",
            "permission_policy": {
              "type": "always_allow"
            }
          }
        ],
        "default_config": {
          "enabled": true,
          "permission_policy": {
            "type": "always_ask"
          }
        },
        "type": "agent_toolset_20260401"
      }
    ],
    "type": "agent",
    "version": 1
  },
  "archived_at": null,
  "created_at": "2026-03-15T10:00:00Z",
  "environment_id": "env_011CZkZ9X2dpNyB7HsEFoRfW",
  "metadata": {},
  "outcome_evaluations": [
    {
      "completed_at": "2026-03-15T10:02:31Z",
      "description": "Produce a 2-page summary as summary.md",
      "explanation": "All five sections present with inline citations.",
      "iteration": 0,
      "outcome_id": "outc_011CZkZRSw2kEfs6ncTVljxP",
      "result": "satisfied",
      "type": "outcome_evaluation"
    }
  ],
  "resources": [
    {
      "id": "sesrsc_011CZkZBJq5dWxk9fVLNcPht",
      "created_at": "2026-03-15T10:00:00Z",
      "file_id": "file_011CNha8iCJcU1wXNR6q4V8w",
      "mount_path": "/uploads/receipt.pdf",
      "type": "file",
      "updated_at": "2026-03-15T10:00:00Z"
    },
    {
      "id": "sesrsc_011CZkZCKr6eXyl0gWMOdQiu",
      "created_at": "2026-03-15T10:00:00Z",
      "mount_path": "/workspace/example-repo",
      "type": "github_repository",
      "updated_at": "2026-03-15T10:00:00Z",
      "url": "https://github.com/example-org/example-repo",
      "checkout": {
        "name": "main",
        "type": "branch"
      }
    }
  ],
  "stats": {
    "active_seconds": 0,
    "duration_seconds": 0
  },
  "status": "idle",
  "title": "Order #1234 inquiry",
  "type": "session",
  "updated_at": "2026-03-15T10:00:00Z",
  "usage": {
    "cache_creation": {
      "ephemeral_1h_input_tokens": 0,
      "ephemeral_5m_input_tokens": 0
    },
    "cache_read_input_tokens": 0,
    "input_tokens": 0,
    "output_tokens": 0
  },
  "vault_ids": [
    "vlt_011CZkZDLs7fYzm1hXNPeRjv"
  ],
  "deployment_id": "deployment_id"
}
```

## Delete Session

`$ ant beta:sessions delete`

**delete** `/v1/sessions/{session_id}`

Delete Session

### Parameters

- `--session-id: string`

  Path parameter session_id

- `--beta: optional array of AnthropicBeta`

  Optional header to specify the beta version(s) you want to use.

### Returns

- `beta_managed_agents_deleted_session: object { id, type }`

  Confirmation that a `session` has been permanently deleted.

  - `id: string`

  - `type: "session_deleted"`

    - `"session_deleted"`

### Example

```cli
ant beta:sessions delete \
  --api-key my-anthropic-api-key \
  --session-id sesn_011CZkZAtmR3yMPDzynEDxu7
```

#### Response

```json
{
  "id": "sesn_011CZkZAtmR3yMPDzynEDxu7",
  "type": "session_deleted"
}
```

## Archive Session

`$ ant beta:sessions archive`

**post** `/v1/sessions/{session_id}/archive`

Archive Session

### Parameters

- `--session-id: string`

  Path parameter session_id

- `--beta: optional array of AnthropicBeta`

  Optional header to specify the beta version(s) you want to use.

### Returns

- `beta_managed_agents_session: object { id, agent, archived_at, 13 more }`

  A Managed Agents `session`.

  - `id: string`

  - `agent: object { id, description, mcp_servers, 8 more }`

    Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time.

    - `id: string`

    - `description: string`

    - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

      - `name: string`

      - `type: "url"`

        - `"url"`

      - `url: string`

    - `model: object { id, speed }`

      Model identifier and configuration.

      - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

        The model that will power your agent.

        See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

        - `"claude-fable-5"`

          Next generation of intelligence for the hardest knowledge work and coding problems

        - `"claude-opus-4-8"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-7"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-6"`

          Most intelligent model for building agents and coding

        - `"claude-sonnet-4-6"`

          Best combination of speed and intelligence

        - `"claude-haiku-4-5"`

          Fastest model with near-frontier intelligence

        - `"claude-haiku-4-5-20251001"`

          Fastest model with near-frontier intelligence

        - `"claude-opus-4-5"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-opus-4-5-20251101"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-sonnet-4-5"`

          High-performance model for agents and coding

        - `"claude-sonnet-4-5-20250929"`

          High-performance model for agents and coding

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `"standard"`

        - `"fast"`

    - `multiagent: object { agents, type }`

      Resolved coordinator topology with full agent definitions for each roster member.

      - `agents: array of BetaManagedAgentsSessionThreadAgent`

        Full `agent` definitions the coordinator may spawn as session threads.

        - `id: string`

        - `description: string`

        - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

          - `name: string`

          - `type: "url"`

          - `url: string`

        - `model: object { id, speed }`

          Model identifier and configuration.

          - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

            The model that will power your agent.

            See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

          - `speed: optional "standard" or "fast"`

            Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `name: string`

        - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

          - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

            A resolved Anthropic-managed skill.

            - `skill_id: string`

            - `type: "anthropic"`

              - `"anthropic"`

            - `version: string`

          - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

            A resolved user-created custom skill.

            - `skill_id: string`

            - `type: "custom"`

              - `"custom"`

            - `version: string`

        - `system: string`

        - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

          - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

            - `configs: array of BetaManagedAgentsAgentToolConfig`

              - `enabled: boolean`

              - `name: "bash" or "edit" or "read" or 5 more`

                Built-in agent tool identifier.

                - `"bash"`

                - `"edit"`

                - `"read"`

                - `"write"`

                - `"glob"`

                - `"grep"`

                - `"web_fetch"`

                - `"web_search"`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                  - `type: "always_allow"`

                    - `"always_allow"`

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

                  - `type: "always_ask"`

                    - `"always_ask"`

            - `default_config: object { enabled, permission_policy }`

              Resolved default configuration for agent tools.

              - `enabled: boolean`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

            - `type: "agent_toolset_20260401"`

              - `"agent_toolset_20260401"`

          - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

            - `configs: array of BetaManagedAgentsMCPToolConfig`

              - `enabled: boolean`

              - `name: string`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

            - `default_config: object { enabled, permission_policy }`

              Resolved default configuration for all tools from an MCP server.

              - `enabled: boolean`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

            - `mcp_server_name: string`

            - `type: "mcp_toolset"`

              - `"mcp_toolset"`

          - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

            A custom tool as returned in API responses.

            - `description: string`

            - `input_schema: object { type, properties, required }`

              JSON Schema for custom tool input parameters.

              - `type: "object"`

              - `properties: optional map[unknown]`

              - `required: optional array of string`

            - `name: string`

            - `type: "custom"`

              - `"custom"`

        - `type: "agent"`

          - `"agent"`

        - `version: number`

      - `type: "coordinator"`

        - `"coordinator"`

    - `name: string`

    - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

      - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

        A resolved Anthropic-managed skill.

      - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

        A resolved user-created custom skill.

    - `system: string`

    - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

      - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

      - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

      - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

        A custom tool as returned in API responses.

    - `type: "agent"`

      - `"agent"`

    - `version: number`

  - `archived_at: string`

    A timestamp in RFC 3339 format

  - `created_at: string`

    A timestamp in RFC 3339 format

  - `environment_id: string`

  - `metadata: map[string]`

  - `outcome_evaluations: array of BetaManagedAgentsOutcomeEvaluationResource`

    Per-outcome evaluation state. One entry per define_outcome event sent to the session.

    - `completed_at: string`

      A timestamp in RFC 3339 format

    - `description: string`

      What the agent should produce.

    - `explanation: string`

      Grader's verdict text from the most recent evaluation. For satisfied, explains why criteria are met; for needs_revision (intermediate), what's missing; for failed, why unrecoverable.

    - `iteration: number`

      0-indexed revision cycle the outcome is currently on.

    - `outcome_id: string`

      Server-generated outc_ ID for this outcome.

    - `result: string`

      Current evaluation state. `pending` before the agent begins work; `running` while producing or revising; `evaluating` while the grader scores; `satisfied`/`max_iterations_reached`/`failed`/`interrupted` are terminal.

    - `type: "outcome_evaluation"`

      - `"outcome_evaluation"`

  - `resources: array of BetaManagedAgentsSessionResource`

    - `beta_managed_agents_github_repository_resource: object { id, created_at, mount_path, 4 more }`

      - `id: string`

      - `created_at: string`

        A timestamp in RFC 3339 format

      - `mount_path: string`

      - `type: "github_repository"`

        - `"github_repository"`

      - `updated_at: string`

        A timestamp in RFC 3339 format

      - `url: string`

      - `checkout: optional BetaManagedAgentsBranchCheckout or BetaManagedAgentsCommitCheckout`

        - `beta_managed_agents_branch_checkout: object { name, type }`

          - `name: string`

            Branch name to check out.

          - `type: "branch"`

            - `"branch"`

        - `beta_managed_agents_commit_checkout: object { sha, type }`

          - `sha: string`

            Full commit SHA to check out.

          - `type: "commit"`

            - `"commit"`

    - `beta_managed_agents_file_resource: object { id, created_at, file_id, 3 more }`

      - `id: string`

      - `created_at: string`

        A timestamp in RFC 3339 format

      - `file_id: string`

      - `mount_path: string`

      - `type: "file"`

        - `"file"`

      - `updated_at: string`

        A timestamp in RFC 3339 format

    - `beta_managed_agents_memory_store_resource: object { memory_store_id, type, access, 4 more }`

      A memory store attached to an agent session.

      - `memory_store_id: string`

        The memory store ID (memstore_...). Must belong to the caller's organization and workspace.

      - `type: "memory_store"`

        - `"memory_store"`

      - `access: optional "read_write" or "read_only"`

        Access mode for an attached memory store.

        - `"read_write"`

        - `"read_only"`

      - `description: optional string`

        Description of the memory store, snapshotted at attach time. Rendered into the agent's system prompt. Empty string when the store has no description.

      - `instructions: optional string`

        Per-attachment guidance for the agent on how to use this store. Rendered into the memory section of the system prompt. Max 4096 chars.

      - `mount_path: optional string`

        Filesystem path where the store is mounted in the session container, e.g. /mnt/memory/user-preferences. Derived from the store's name. Output-only.

      - `name: optional string`

        Display name of the memory store, snapshotted at attach time. Later edits to the store's name do not propagate to this resource.

  - `stats: object { active_seconds, duration_seconds }`

    Timing statistics for a session.

    - `active_seconds: optional number`

      Cumulative time in seconds the session spent in running status. Excludes idle time.

    - `duration_seconds: optional number`

      Elapsed time since session creation in seconds. For terminated sessions, frozen at the final update.

  - `status: "rescheduling" or "running" or "idle" or "terminated"`

    SessionStatus enum

    - `"rescheduling"`

    - `"running"`

    - `"idle"`

    - `"terminated"`

  - `title: string`

  - `type: "session"`

    - `"session"`

  - `updated_at: string`

    A timestamp in RFC 3339 format

  - `usage: object { cache_creation, cache_read_input_tokens, input_tokens, output_tokens }`

    Cumulative token usage for a session across all turns.

    - `cache_creation: optional object { ephemeral_1h_input_tokens, ephemeral_5m_input_tokens }`

      Prompt-cache creation token usage broken down by cache lifetime.

      - `ephemeral_1h_input_tokens: optional number`

        Tokens used to create 1-hour ephemeral cache entries.

      - `ephemeral_5m_input_tokens: optional number`

        Tokens used to create 5-minute ephemeral cache entries.

    - `cache_read_input_tokens: optional number`

      Total tokens read from prompt cache.

    - `input_tokens: optional number`

      Total input tokens consumed across all turns.

    - `output_tokens: optional number`

      Total output tokens generated across all turns.

  - `vault_ids: array of string`

    Vault IDs attached to the session at creation. Empty when no vaults were supplied.

  - `deployment_id: optional string`

    Deployment ID when the session was created from a deployment reference. Null otherwise.

### Example

```cli
ant beta:sessions archive \
  --api-key my-anthropic-api-key \
  --session-id sesn_011CZkZAtmR3yMPDzynEDxu7
```

#### Response

```json
{
  "id": "sesn_011CZkZAtmR3yMPDzynEDxu7",
  "agent": {
    "id": "agent_011CZkYpogX7uDKUyvBTophP",
    "description": "A general-purpose starter agent.",
    "mcp_servers": [
      {
        "name": "example-mcp",
        "type": "url",
        "url": "https://example-server.modelcontextprotocol.io/sse"
      }
    ],
    "model": {
      "id": "claude-sonnet-4-6",
      "speed": "standard"
    },
    "multiagent": {
      "agents": [
        {
          "id": "agent_011CZkYqphY8vELVzwCUpqiQ",
          "description": "A focused research subagent.",
          "mcp_servers": [
            {
              "name": "example-mcp",
              "type": "url",
              "url": "https://example-server.modelcontextprotocol.io/sse"
            }
          ],
          "model": {
            "id": "claude-sonnet-4-6",
            "speed": "standard"
          },
          "name": "Researcher",
          "skills": [
            {
              "skill_id": "xlsx",
              "type": "anthropic",
              "version": "1"
            }
          ],
          "system": "You are a research subagent that gathers and summarises sources for the coordinating agent.",
          "tools": [
            {
              "configs": [
                {
                  "enabled": true,
                  "name": "bash",
                  "permission_policy": {
                    "type": "always_allow"
                  }
                }
              ],
              "default_config": {
                "enabled": true,
                "permission_policy": {
                  "type": "always_ask"
                }
              },
              "type": "agent_toolset_20260401"
            }
          ],
          "type": "agent",
          "version": 1
        }
      ],
      "type": "coordinator"
    },
    "name": "My First Agent",
    "skills": [
      {
        "skill_id": "xlsx",
        "type": "anthropic",
        "version": "1"
      },
      {
        "skill_id": "skill_011CZkZFNu9hAbo3jZPRgTlx",
        "type": "custom",
        "version": "2"
      }
    ],
    "system": "You are a general-purpose agent that can research, write code, run commands, and use connected tools to complete the user's task end to end.",
    "tools": [
      {
        "configs": [
          {
            "enabled": true,
            "name": "bash",
            "permission_policy": {
              "type": "always_allow"
            }
          }
        ],
        "default_config": {
          "enabled": true,
          "permission_policy": {
            "type": "always_ask"
          }
        },
        "type": "agent_toolset_20260401"
      }
    ],
    "type": "agent",
    "version": 1
  },
  "archived_at": null,
  "created_at": "2026-03-15T10:00:00Z",
  "environment_id": "env_011CZkZ9X2dpNyB7HsEFoRfW",
  "metadata": {},
  "outcome_evaluations": [
    {
      "completed_at": "2026-03-15T10:02:31Z",
      "description": "Produce a 2-page summary as summary.md",
      "explanation": "All five sections present with inline citations.",
      "iteration": 0,
      "outcome_id": "outc_011CZkZRSw2kEfs6ncTVljxP",
      "result": "satisfied",
      "type": "outcome_evaluation"
    }
  ],
  "resources": [
    {
      "id": "sesrsc_011CZkZBJq5dWxk9fVLNcPht",
      "created_at": "2026-03-15T10:00:00Z",
      "file_id": "file_011CNha8iCJcU1wXNR6q4V8w",
      "mount_path": "/uploads/receipt.pdf",
      "type": "file",
      "updated_at": "2026-03-15T10:00:00Z"
    },
    {
      "id": "sesrsc_011CZkZCKr6eXyl0gWMOdQiu",
      "created_at": "2026-03-15T10:00:00Z",
      "mount_path": "/workspace/example-repo",
      "type": "github_repository",
      "updated_at": "2026-03-15T10:00:00Z",
      "url": "https://github.com/example-org/example-repo",
      "checkout": {
        "name": "main",
        "type": "branch"
      }
    }
  ],
  "stats": {
    "active_seconds": 0,
    "duration_seconds": 0
  },
  "status": "idle",
  "title": "Order #1234 inquiry",
  "type": "session",
  "updated_at": "2026-03-15T10:00:00Z",
  "usage": {
    "cache_creation": {
      "ephemeral_1h_input_tokens": 0,
      "ephemeral_5m_input_tokens": 0
    },
    "cache_read_input_tokens": 0,
    "input_tokens": 0,
    "output_tokens": 0
  },
  "vault_ids": [
    "vlt_011CZkZDLs7fYzm1hXNPeRjv"
  ],
  "deployment_id": "deployment_id"
}
```

## Domain Types

### Beta Managed Agents Agent Params

- `beta_managed_agents_agent_params: object { id, type, version }`

  Specification for an Agent. Provide a specific `version` or use the short-form `agent="agent_id"` for the most recent version

  - `id: string`

    The `agent` ID.

  - `type: "agent"`

    - `"agent"`

  - `version: optional number`

    The specific `agent` version to use. Omit to use the latest version. Must be at least 1 if specified.

### Beta Managed Agents Branch Checkout

- `beta_managed_agents_branch_checkout: object { name, type }`

  - `name: string`

    Branch name to check out.

  - `type: "branch"`

    - `"branch"`

### Beta Managed Agents Cache Creation Usage

- `beta_managed_agents_cache_creation_usage: object { ephemeral_1h_input_tokens, ephemeral_5m_input_tokens }`

  Prompt-cache creation token usage broken down by cache lifetime.

  - `ephemeral_1h_input_tokens: optional number`

    Tokens used to create 1-hour ephemeral cache entries.

  - `ephemeral_5m_input_tokens: optional number`

    Tokens used to create 5-minute ephemeral cache entries.

### Beta Managed Agents Commit Checkout

- `beta_managed_agents_commit_checkout: object { sha, type }`

  - `sha: string`

    Full commit SHA to check out.

  - `type: "commit"`

    - `"commit"`

### Beta Managed Agents Deleted Session

- `beta_managed_agents_deleted_session: object { id, type }`

  Confirmation that a `session` has been permanently deleted.

  - `id: string`

  - `type: "session_deleted"`

    - `"session_deleted"`

### Beta Managed Agents File Resource Params

- `beta_managed_agents_file_resource_params: object { file_id, type, mount_path }`

  Mount a file uploaded via the Files API into the session.

  - `file_id: string`

    ID of a previously uploaded file.

  - `type: "file"`

    - `"file"`

  - `mount_path: optional string`

    Mount path in the container. Defaults to `/mnt/session/uploads/<file_id>`.

### Beta Managed Agents GitHub Repository Resource Params

- `beta_managed_agents_github_repository_resource_params: object { authorization_token, type, url, 2 more }`

  Mount a GitHub repository into the session's container.

  - `authorization_token: string`

    GitHub authorization token used to clone the repository.

  - `type: "github_repository"`

    - `"github_repository"`

  - `url: string`

    Github URL of the repository

  - `checkout: optional BetaManagedAgentsBranchCheckout or BetaManagedAgentsCommitCheckout`

    Branch or commit to check out. Defaults to the repository's default branch.

    - `beta_managed_agents_branch_checkout: object { name, type }`

      - `name: string`

        Branch name to check out.

      - `type: "branch"`

        - `"branch"`

    - `beta_managed_agents_commit_checkout: object { sha, type }`

      - `sha: string`

        Full commit SHA to check out.

      - `type: "commit"`

        - `"commit"`

  - `mount_path: optional string`

    Mount path in the container. Defaults to `/workspace/<repo-name>`.

### Beta Managed Agents Memory Store Resource Param

- `beta_managed_agents_memory_store_resource_param: object { memory_store_id, type, access, instructions }`

  Parameters for attaching a memory store to an agent session.

  - `memory_store_id: string`

    The memory store ID (memstore_...). Must belong to the caller's organization and workspace.

  - `type: "memory_store"`

    - `"memory_store"`

  - `access: optional "read_write" or "read_only"`

    Access mode for an attached memory store.

    - `"read_write"`

    - `"read_only"`

  - `instructions: optional string`

    Per-attachment guidance for the agent on how to use this store. Rendered into the memory section of the system prompt. Max 4096 chars.

### Beta Managed Agents Multiagent

- `beta_managed_agents_multiagent: object { agents, type }`

  Resolved coordinator topology with a concrete agent roster.

  - `agents: array of BetaManagedAgentsAgentReference`

    Agents the coordinator may spawn as session threads, each resolved to a specific version.

    - `id: string`

    - `type: "agent"`

      - `"agent"`

    - `version: number`

  - `type: "coordinator"`

    - `"coordinator"`

### Beta Managed Agents Multiagent Params

- `beta_managed_agents_multiagent_params: object { agents, type }`

  A coordinator topology: the session's primary thread orchestrates work by spawning session threads, each running an agent drawn from the `agents` roster.

  - `agents: array of BetaManagedAgentsMultiagentRosterEntryParams`

    Agents the coordinator may spawn as session threads. 1–20 entries. Each entry is an agent ID string, a versioned `{"type":"agent","id","version"}` reference, or `{"type":"self"}` to allow recursive self-invocation. Entries must reference distinct agents (after resolving `self` and string forms); at most one `self`. Referenced agents must exist, must not be archived, and must not themselves have `multiagent` set (depth limit 1).

    - `union_member_0: string`

    - `beta_managed_agents_agent_params: object { id, type, version }`

      Specification for an Agent. Provide a specific `version` or use the short-form `agent="agent_id"` for the most recent version

      - `id: string`

        The `agent` ID.

      - `type: "agent"`

        - `"agent"`

      - `version: optional number`

        The specific `agent` version to use. Omit to use the latest version. Must be at least 1 if specified.

    - `beta_managed_agents_multiagent_self_params: object { type }`

      Sentinel roster entry meaning "the agent that owns this configuration". Resolved server-side to a concrete agent reference.

      - `type: "self"`

        - `"self"`

  - `type: "coordinator"`

    - `"coordinator"`

### Beta Managed Agents Multiagent Roster Entry Params

- `beta_managed_agents_multiagent_roster_entry_params: string or BetaManagedAgentsAgentParams or BetaManagedAgentsMultiagentSelfParams`

  An entry in a multiagent roster: an agent ID string, a versioned agent reference, or `self`.

  - `union_member_0: string`

  - `beta_managed_agents_agent_params: object { id, type, version }`

    Specification for an Agent. Provide a specific `version` or use the short-form `agent="agent_id"` for the most recent version

    - `id: string`

      The `agent` ID.

    - `type: "agent"`

      - `"agent"`

    - `version: optional number`

      The specific `agent` version to use. Omit to use the latest version. Must be at least 1 if specified.

  - `beta_managed_agents_multiagent_self_params: object { type }`

    Sentinel roster entry meaning "the agent that owns this configuration". Resolved server-side to a concrete agent reference.

    - `type: "self"`

      - `"self"`

### Beta Managed Agents Outcome Evaluation Resource

- `beta_managed_agents_outcome_evaluation_resource: object { completed_at, description, explanation, 4 more }`

  Evaluation state for a single outcome defined via a define_outcome event.

  - `completed_at: string`

    A timestamp in RFC 3339 format

  - `description: string`

    What the agent should produce.

  - `explanation: string`

    Grader's verdict text from the most recent evaluation. For satisfied, explains why criteria are met; for needs_revision (intermediate), what's missing; for failed, why unrecoverable.

  - `iteration: number`

    0-indexed revision cycle the outcome is currently on.

  - `outcome_id: string`

    Server-generated outc_ ID for this outcome.

  - `result: string`

    Current evaluation state. `pending` before the agent begins work; `running` while producing or revising; `evaluating` while the grader scores; `satisfied`/`max_iterations_reached`/`failed`/`interrupted` are terminal.

  - `type: "outcome_evaluation"`

    - `"outcome_evaluation"`

### Beta Managed Agents Session

- `beta_managed_agents_session: object { id, agent, archived_at, 13 more }`

  A Managed Agents `session`.

  - `id: string`

  - `agent: object { id, description, mcp_servers, 8 more }`

    Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time.

    - `id: string`

    - `description: string`

    - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

      - `name: string`

      - `type: "url"`

        - `"url"`

      - `url: string`

    - `model: object { id, speed }`

      Model identifier and configuration.

      - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

        The model that will power your agent.

        See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

        - `"claude-fable-5"`

          Next generation of intelligence for the hardest knowledge work and coding problems

        - `"claude-opus-4-8"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-7"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-6"`

          Most intelligent model for building agents and coding

        - `"claude-sonnet-4-6"`

          Best combination of speed and intelligence

        - `"claude-haiku-4-5"`

          Fastest model with near-frontier intelligence

        - `"claude-haiku-4-5-20251001"`

          Fastest model with near-frontier intelligence

        - `"claude-opus-4-5"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-opus-4-5-20251101"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-sonnet-4-5"`

          High-performance model for agents and coding

        - `"claude-sonnet-4-5-20250929"`

          High-performance model for agents and coding

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `"standard"`

        - `"fast"`

    - `multiagent: object { agents, type }`

      Resolved coordinator topology with full agent definitions for each roster member.

      - `agents: array of BetaManagedAgentsSessionThreadAgent`

        Full `agent` definitions the coordinator may spawn as session threads.

        - `id: string`

        - `description: string`

        - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

          - `name: string`

          - `type: "url"`

          - `url: string`

        - `model: object { id, speed }`

          Model identifier and configuration.

          - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

            The model that will power your agent.

            See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

          - `speed: optional "standard" or "fast"`

            Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `name: string`

        - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

          - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

            A resolved Anthropic-managed skill.

            - `skill_id: string`

            - `type: "anthropic"`

              - `"anthropic"`

            - `version: string`

          - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

            A resolved user-created custom skill.

            - `skill_id: string`

            - `type: "custom"`

              - `"custom"`

            - `version: string`

        - `system: string`

        - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

          - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

            - `configs: array of BetaManagedAgentsAgentToolConfig`

              - `enabled: boolean`

              - `name: "bash" or "edit" or "read" or 5 more`

                Built-in agent tool identifier.

                - `"bash"`

                - `"edit"`

                - `"read"`

                - `"write"`

                - `"glob"`

                - `"grep"`

                - `"web_fetch"`

                - `"web_search"`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                  - `type: "always_allow"`

                    - `"always_allow"`

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

                  - `type: "always_ask"`

                    - `"always_ask"`

            - `default_config: object { enabled, permission_policy }`

              Resolved default configuration for agent tools.

              - `enabled: boolean`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

            - `type: "agent_toolset_20260401"`

              - `"agent_toolset_20260401"`

          - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

            - `configs: array of BetaManagedAgentsMCPToolConfig`

              - `enabled: boolean`

              - `name: string`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

            - `default_config: object { enabled, permission_policy }`

              Resolved default configuration for all tools from an MCP server.

              - `enabled: boolean`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

            - `mcp_server_name: string`

            - `type: "mcp_toolset"`

              - `"mcp_toolset"`

          - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

            A custom tool as returned in API responses.

            - `description: string`

            - `input_schema: object { type, properties, required }`

              JSON Schema for custom tool input parameters.

              - `type: "object"`

              - `properties: optional map[unknown]`

              - `required: optional array of string`

            - `name: string`

            - `type: "custom"`

              - `"custom"`

        - `type: "agent"`

          - `"agent"`

        - `version: number`

      - `type: "coordinator"`

        - `"coordinator"`

    - `name: string`

    - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

      - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

        A resolved Anthropic-managed skill.

      - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

        A resolved user-created custom skill.

    - `system: string`

    - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

      - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

      - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

      - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

        A custom tool as returned in API responses.

    - `type: "agent"`

      - `"agent"`

    - `version: number`

  - `archived_at: string`

    A timestamp in RFC 3339 format

  - `created_at: string`

    A timestamp in RFC 3339 format

  - `environment_id: string`

  - `metadata: map[string]`

  - `outcome_evaluations: array of BetaManagedAgentsOutcomeEvaluationResource`

    Per-outcome evaluation state. One entry per define_outcome event sent to the session.

    - `completed_at: string`

      A timestamp in RFC 3339 format

    - `description: string`

      What the agent should produce.

    - `explanation: string`

      Grader's verdict text from the most recent evaluation. For satisfied, explains why criteria are met; for needs_revision (intermediate), what's missing; for failed, why unrecoverable.

    - `iteration: number`

      0-indexed revision cycle the outcome is currently on.

    - `outcome_id: string`

      Server-generated outc_ ID for this outcome.

    - `result: string`

      Current evaluation state. `pending` before the agent begins work; `running` while producing or revising; `evaluating` while the grader scores; `satisfied`/`max_iterations_reached`/`failed`/`interrupted` are terminal.

    - `type: "outcome_evaluation"`

      - `"outcome_evaluation"`

  - `resources: array of BetaManagedAgentsSessionResource`

    - `beta_managed_agents_github_repository_resource: object { id, created_at, mount_path, 4 more }`

      - `id: string`

      - `created_at: string`

        A timestamp in RFC 3339 format

      - `mount_path: string`

      - `type: "github_repository"`

        - `"github_repository"`

      - `updated_at: string`

        A timestamp in RFC 3339 format

      - `url: string`

      - `checkout: optional BetaManagedAgentsBranchCheckout or BetaManagedAgentsCommitCheckout`

        - `beta_managed_agents_branch_checkout: object { name, type }`

          - `name: string`

            Branch name to check out.

          - `type: "branch"`

            - `"branch"`

        - `beta_managed_agents_commit_checkout: object { sha, type }`

          - `sha: string`

            Full commit SHA to check out.

          - `type: "commit"`

            - `"commit"`

    - `beta_managed_agents_file_resource: object { id, created_at, file_id, 3 more }`

      - `id: string`

      - `created_at: string`

        A timestamp in RFC 3339 format

      - `file_id: string`

      - `mount_path: string`

      - `type: "file"`

        - `"file"`

      - `updated_at: string`

        A timestamp in RFC 3339 format

    - `beta_managed_agents_memory_store_resource: object { memory_store_id, type, access, 4 more }`

      A memory store attached to an agent session.

      - `memory_store_id: string`

        The memory store ID (memstore_...). Must belong to the caller's organization and workspace.

      - `type: "memory_store"`

        - `"memory_store"`

      - `access: optional "read_write" or "read_only"`

        Access mode for an attached memory store.

        - `"read_write"`

        - `"read_only"`

      - `description: optional string`

        Description of the memory store, snapshotted at attach time. Rendered into the agent's system prompt. Empty string when the store has no description.

      - `instructions: optional string`

        Per-attachment guidance for the agent on how to use this store. Rendered into the memory section of the system prompt. Max 4096 chars.

      - `mount_path: optional string`

        Filesystem path where the store is mounted in the session container, e.g. /mnt/memory/user-preferences. Derived from the store's name. Output-only.

      - `name: optional string`

        Display name of the memory store, snapshotted at attach time. Later edits to the store's name do not propagate to this resource.

  - `stats: object { active_seconds, duration_seconds }`

    Timing statistics for a session.

    - `active_seconds: optional number`

      Cumulative time in seconds the session spent in running status. Excludes idle time.

    - `duration_seconds: optional number`

      Elapsed time since session creation in seconds. For terminated sessions, frozen at the final update.

  - `status: "rescheduling" or "running" or "idle" or "terminated"`

    SessionStatus enum

    - `"rescheduling"`

    - `"running"`

    - `"idle"`

    - `"terminated"`

  - `title: string`

  - `type: "session"`

    - `"session"`

  - `updated_at: string`

    A timestamp in RFC 3339 format

  - `usage: object { cache_creation, cache_read_input_tokens, input_tokens, output_tokens }`

    Cumulative token usage for a session across all turns.

    - `cache_creation: optional object { ephemeral_1h_input_tokens, ephemeral_5m_input_tokens }`

      Prompt-cache creation token usage broken down by cache lifetime.

      - `ephemeral_1h_input_tokens: optional number`

        Tokens used to create 1-hour ephemeral cache entries.

      - `ephemeral_5m_input_tokens: optional number`

        Tokens used to create 5-minute ephemeral cache entries.

    - `cache_read_input_tokens: optional number`

      Total tokens read from prompt cache.

    - `input_tokens: optional number`

      Total input tokens consumed across all turns.

    - `output_tokens: optional number`

      Total output tokens generated across all turns.

  - `vault_ids: array of string`

    Vault IDs attached to the session at creation. Empty when no vaults were supplied.

  - `deployment_id: optional string`

    Deployment ID when the session was created from a deployment reference. Null otherwise.

### Beta Managed Agents Session Agent

- `beta_managed_agents_session_agent: object { id, description, mcp_servers, 8 more }`

  Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time.

  - `id: string`

  - `description: string`

  - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

    - `name: string`

    - `type: "url"`

      - `"url"`

    - `url: string`

  - `model: object { id, speed }`

    Model identifier and configuration.

    - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

      The model that will power your agent.

      See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

      - `"claude-fable-5"`

        Next generation of intelligence for the hardest knowledge work and coding problems

      - `"claude-opus-4-8"`

        Frontier intelligence for long-running agents and coding

      - `"claude-opus-4-7"`

        Frontier intelligence for long-running agents and coding

      - `"claude-opus-4-6"`

        Most intelligent model for building agents and coding

      - `"claude-sonnet-4-6"`

        Best combination of speed and intelligence

      - `"claude-haiku-4-5"`

        Fastest model with near-frontier intelligence

      - `"claude-haiku-4-5-20251001"`

        Fastest model with near-frontier intelligence

      - `"claude-opus-4-5"`

        Premium model combining maximum intelligence with practical performance

      - `"claude-opus-4-5-20251101"`

        Premium model combining maximum intelligence with practical performance

      - `"claude-sonnet-4-5"`

        High-performance model for agents and coding

      - `"claude-sonnet-4-5-20250929"`

        High-performance model for agents and coding

    - `speed: optional "standard" or "fast"`

      Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

      - `"standard"`

      - `"fast"`

  - `multiagent: object { agents, type }`

    Resolved coordinator topology with full agent definitions for each roster member.

    - `agents: array of BetaManagedAgentsSessionThreadAgent`

      Full `agent` definitions the coordinator may spawn as session threads.

      - `id: string`

      - `description: string`

      - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

        - `name: string`

        - `type: "url"`

        - `url: string`

      - `model: object { id, speed }`

        Model identifier and configuration.

        - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

          The model that will power your agent.

          See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

        - `speed: optional "standard" or "fast"`

          Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

      - `name: string`

      - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

        - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

          A resolved Anthropic-managed skill.

          - `skill_id: string`

          - `type: "anthropic"`

            - `"anthropic"`

          - `version: string`

        - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

          A resolved user-created custom skill.

          - `skill_id: string`

          - `type: "custom"`

            - `"custom"`

          - `version: string`

      - `system: string`

      - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

        - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

          - `configs: array of BetaManagedAgentsAgentToolConfig`

            - `enabled: boolean`

            - `name: "bash" or "edit" or "read" or 5 more`

              Built-in agent tool identifier.

              - `"bash"`

              - `"edit"`

              - `"read"`

              - `"write"`

              - `"glob"`

              - `"grep"`

              - `"web_fetch"`

              - `"web_search"`

            - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

              Permission policy for tool execution.

              - `beta_managed_agents_always_allow_policy: object { type }`

                Tool calls are automatically approved without user confirmation.

                - `type: "always_allow"`

                  - `"always_allow"`

              - `beta_managed_agents_always_ask_policy: object { type }`

                Tool calls require user confirmation before execution.

                - `type: "always_ask"`

                  - `"always_ask"`

          - `default_config: object { enabled, permission_policy }`

            Resolved default configuration for agent tools.

            - `enabled: boolean`

            - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

              Permission policy for tool execution.

              - `beta_managed_agents_always_allow_policy: object { type }`

                Tool calls are automatically approved without user confirmation.

              - `beta_managed_agents_always_ask_policy: object { type }`

                Tool calls require user confirmation before execution.

          - `type: "agent_toolset_20260401"`

            - `"agent_toolset_20260401"`

        - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

          - `configs: array of BetaManagedAgentsMCPToolConfig`

            - `enabled: boolean`

            - `name: string`

            - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

              Permission policy for tool execution.

              - `beta_managed_agents_always_allow_policy: object { type }`

                Tool calls are automatically approved without user confirmation.

              - `beta_managed_agents_always_ask_policy: object { type }`

                Tool calls require user confirmation before execution.

          - `default_config: object { enabled, permission_policy }`

            Resolved default configuration for all tools from an MCP server.

            - `enabled: boolean`

            - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

              Permission policy for tool execution.

              - `beta_managed_agents_always_allow_policy: object { type }`

                Tool calls are automatically approved without user confirmation.

              - `beta_managed_agents_always_ask_policy: object { type }`

                Tool calls require user confirmation before execution.

          - `mcp_server_name: string`

          - `type: "mcp_toolset"`

            - `"mcp_toolset"`

        - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

          A custom tool as returned in API responses.

          - `description: string`

          - `input_schema: object { type, properties, required }`

            JSON Schema for custom tool input parameters.

            - `type: "object"`

            - `properties: optional map[unknown]`

            - `required: optional array of string`

          - `name: string`

          - `type: "custom"`

            - `"custom"`

      - `type: "agent"`

        - `"agent"`

      - `version: number`

    - `type: "coordinator"`

      - `"coordinator"`

  - `name: string`

  - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

    - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

      A resolved Anthropic-managed skill.

    - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

      A resolved user-created custom skill.

  - `system: string`

  - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

    - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

    - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

    - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

      A custom tool as returned in API responses.

  - `type: "agent"`

    - `"agent"`

  - `version: number`

### Beta Managed Agents Session Agent Update

- `beta_managed_agents_session_agent_update: object { mcp_servers, tools }`

  Mid-session agent configuration update. Only `tools` and `mcp_servers` are updatable. Full replacement: the provided array becomes the new value. To preserve existing entries, GET the session, modify the array, and POST it back.

  - `mcp_servers: optional array of BetaManagedAgentsURLMCPServerParams`

    Replacement MCP server list. Full replacement: the provided array becomes the new value. Send an empty array to clear; omit to preserve.

    - `name: string`

      Unique name for this server, referenced by mcp_toolset configurations. 1-255 characters.

    - `type: "url"`

      - `"url"`

    - `url: string`

      Endpoint URL for the MCP server.

  - `tools: optional array of BetaManagedAgentsAgentToolset20260401Params or BetaManagedAgentsMCPToolsetParams or BetaManagedAgentsCustomToolParams`

    Replacement tool list. Full replacement: the provided array becomes the new value. Send an empty array to clear; omit to preserve.

    - `beta_managed_agents_agent_toolset20260401_params: object { type, configs, default_config }`

      Configuration for built-in agent tools. Use this to enable or disable groups of tools available to the agent.

      - `type: "agent_toolset_20260401"`

        - `"agent_toolset_20260401"`

      - `configs: optional array of BetaManagedAgentsAgentToolConfigParams`

        Per-tool configuration overrides.

        - `name: "bash" or "edit" or "read" or 5 more`

          Built-in agent tool identifier.

          - `"bash"`

          - `"edit"`

          - `"read"`

          - `"write"`

          - `"glob"`

          - `"grep"`

          - `"web_fetch"`

          - `"web_search"`

        - `enabled: optional boolean`

          Whether this tool is enabled and available to Claude. Overrides the default_config setting.

        - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

          Permission policy for tool execution.

          - `beta_managed_agents_always_allow_policy: object { type }`

            Tool calls are automatically approved without user confirmation.

            - `type: "always_allow"`

              - `"always_allow"`

          - `beta_managed_agents_always_ask_policy: object { type }`

            Tool calls require user confirmation before execution.

            - `type: "always_ask"`

              - `"always_ask"`

      - `default_config: optional object { enabled, permission_policy }`

        Default configuration for all tools in a toolset.

        - `enabled: optional boolean`

          Whether tools are enabled and available to Claude by default. Defaults to true if not specified.

        - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

          Permission policy for tool execution.

          - `beta_managed_agents_always_allow_policy: object { type }`

            Tool calls are automatically approved without user confirmation.

          - `beta_managed_agents_always_ask_policy: object { type }`

            Tool calls require user confirmation before execution.

    - `beta_managed_agents_mcp_toolset_params: object { mcp_server_name, type, configs, default_config }`

      Configuration for tools from an MCP server defined in `mcp_servers`.

      - `mcp_server_name: string`

        Name of the MCP server. Must match a server name from the mcp_servers array. 1-255 characters.

      - `type: "mcp_toolset"`

        - `"mcp_toolset"`

      - `configs: optional array of BetaManagedAgentsMCPToolConfigParams`

        Per-tool configuration overrides.

        - `name: string`

          Name of the MCP tool to configure. 1-128 characters.

        - `enabled: optional boolean`

          Whether this tool is enabled. Overrides the `default_config` setting.

        - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

          Permission policy for tool execution.

          - `beta_managed_agents_always_allow_policy: object { type }`

            Tool calls are automatically approved without user confirmation.

          - `beta_managed_agents_always_ask_policy: object { type }`

            Tool calls require user confirmation before execution.

      - `default_config: optional object { enabled, permission_policy }`

        Default configuration for all tools from an MCP server.

        - `enabled: optional boolean`

          Whether tools are enabled by default. Defaults to true if not specified.

        - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

          Permission policy for tool execution.

          - `beta_managed_agents_always_allow_policy: object { type }`

            Tool calls are automatically approved without user confirmation.

          - `beta_managed_agents_always_ask_policy: object { type }`

            Tool calls require user confirmation before execution.

    - `beta_managed_agents_custom_tool_params: object { description, input_schema, name, type }`

      A custom tool that is executed by the API client rather than the agent. When the agent calls this tool, an `agent.custom_tool_use` event is emitted and the session goes idle, waiting for the client to provide the result via a `user.custom_tool_result` event.

      - `description: string`

        Description of what the tool does, shown to the agent to help it decide when to use the tool. 1-1024 characters.

      - `input_schema: object { type, properties, required }`

        JSON Schema for custom tool input parameters.

        - `type: "object"`

        - `properties: optional map[unknown]`

        - `required: optional array of string`

      - `name: string`

        Unique name for the tool. 1-128 characters; letters, digits, underscores, and hyphens.

      - `type: "custom"`

        - `"custom"`

### Beta Managed Agents Session Multiagent Coordinator

- `beta_managed_agents_session_multiagent_coordinator: object { agents, type }`

  Resolved coordinator topology with full agent definitions for each roster member.

  - `agents: array of BetaManagedAgentsSessionThreadAgent`

    Full `agent` definitions the coordinator may spawn as session threads.

    - `id: string`

    - `description: string`

    - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

      - `name: string`

      - `type: "url"`

        - `"url"`

      - `url: string`

    - `model: object { id, speed }`

      Model identifier and configuration.

      - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

        The model that will power your agent.

        See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

        - `"claude-fable-5"`

          Next generation of intelligence for the hardest knowledge work and coding problems

        - `"claude-opus-4-8"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-7"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-6"`

          Most intelligent model for building agents and coding

        - `"claude-sonnet-4-6"`

          Best combination of speed and intelligence

        - `"claude-haiku-4-5"`

          Fastest model with near-frontier intelligence

        - `"claude-haiku-4-5-20251001"`

          Fastest model with near-frontier intelligence

        - `"claude-opus-4-5"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-opus-4-5-20251101"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-sonnet-4-5"`

          High-performance model for agents and coding

        - `"claude-sonnet-4-5-20250929"`

          High-performance model for agents and coding

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `"standard"`

        - `"fast"`

    - `name: string`

    - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

      - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

        A resolved Anthropic-managed skill.

        - `skill_id: string`

        - `type: "anthropic"`

          - `"anthropic"`

        - `version: string`

      - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

        A resolved user-created custom skill.

        - `skill_id: string`

        - `type: "custom"`

          - `"custom"`

        - `version: string`

    - `system: string`

    - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

      - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

        - `configs: array of BetaManagedAgentsAgentToolConfig`

          - `enabled: boolean`

          - `name: "bash" or "edit" or "read" or 5 more`

            Built-in agent tool identifier.

            - `"bash"`

            - `"edit"`

            - `"read"`

            - `"write"`

            - `"glob"`

            - `"grep"`

            - `"web_fetch"`

            - `"web_search"`

          - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

            Permission policy for tool execution.

            - `beta_managed_agents_always_allow_policy: object { type }`

              Tool calls are automatically approved without user confirmation.

              - `type: "always_allow"`

                - `"always_allow"`

            - `beta_managed_agents_always_ask_policy: object { type }`

              Tool calls require user confirmation before execution.

              - `type: "always_ask"`

                - `"always_ask"`

        - `default_config: object { enabled, permission_policy }`

          Resolved default configuration for agent tools.

          - `enabled: boolean`

          - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

            Permission policy for tool execution.

            - `beta_managed_agents_always_allow_policy: object { type }`

              Tool calls are automatically approved without user confirmation.

            - `beta_managed_agents_always_ask_policy: object { type }`

              Tool calls require user confirmation before execution.

        - `type: "agent_toolset_20260401"`

          - `"agent_toolset_20260401"`

      - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

        - `configs: array of BetaManagedAgentsMCPToolConfig`

          - `enabled: boolean`

          - `name: string`

          - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

            Permission policy for tool execution.

            - `beta_managed_agents_always_allow_policy: object { type }`

              Tool calls are automatically approved without user confirmation.

            - `beta_managed_agents_always_ask_policy: object { type }`

              Tool calls require user confirmation before execution.

        - `default_config: object { enabled, permission_policy }`

          Resolved default configuration for all tools from an MCP server.

          - `enabled: boolean`

          - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

            Permission policy for tool execution.

            - `beta_managed_agents_always_allow_policy: object { type }`

              Tool calls are automatically approved without user confirmation.

            - `beta_managed_agents_always_ask_policy: object { type }`

              Tool calls require user confirmation before execution.

        - `mcp_server_name: string`

        - `type: "mcp_toolset"`

          - `"mcp_toolset"`

      - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

        A custom tool as returned in API responses.

        - `description: string`

        - `input_schema: object { type, properties, required }`

          JSON Schema for custom tool input parameters.

          - `type: "object"`

          - `properties: optional map[unknown]`

          - `required: optional array of string`

        - `name: string`

        - `type: "custom"`

          - `"custom"`

    - `type: "agent"`

      - `"agent"`

    - `version: number`

  - `type: "coordinator"`

    - `"coordinator"`

### Beta Managed Agents Session Stats

- `beta_managed_agents_session_stats: object { active_seconds, duration_seconds }`

  Timing statistics for a session.

  - `active_seconds: optional number`

    Cumulative time in seconds the session spent in running status. Excludes idle time.

  - `duration_seconds: optional number`

    Elapsed time since session creation in seconds. For terminated sessions, frozen at the final update.

### Beta Managed Agents Session Updated Event

- `beta_managed_agents_session_updated_event: object { id, processed_at, type, 3 more }`

  Emitted when an UpdateSession request changed at least one field. Carries only the fields that changed; absent fields were not part of the update. The new configuration applies from the next turn.

  - `id: string`

    Unique identifier for this event.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `type: "session.updated"`

    - `"session.updated"`

  - `agent: optional object { id, description, mcp_servers, 8 more }`

    Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time.

    - `id: string`

    - `description: string`

    - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

      - `name: string`

      - `type: "url"`

        - `"url"`

      - `url: string`

    - `model: object { id, speed }`

      Model identifier and configuration.

      - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

        The model that will power your agent.

        See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

        - `"claude-fable-5"`

          Next generation of intelligence for the hardest knowledge work and coding problems

        - `"claude-opus-4-8"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-7"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-6"`

          Most intelligent model for building agents and coding

        - `"claude-sonnet-4-6"`

          Best combination of speed and intelligence

        - `"claude-haiku-4-5"`

          Fastest model with near-frontier intelligence

        - `"claude-haiku-4-5-20251001"`

          Fastest model with near-frontier intelligence

        - `"claude-opus-4-5"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-opus-4-5-20251101"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-sonnet-4-5"`

          High-performance model for agents and coding

        - `"claude-sonnet-4-5-20250929"`

          High-performance model for agents and coding

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `"standard"`

        - `"fast"`

    - `multiagent: object { agents, type }`

      Resolved coordinator topology with full agent definitions for each roster member.

      - `agents: array of BetaManagedAgentsSessionThreadAgent`

        Full `agent` definitions the coordinator may spawn as session threads.

        - `id: string`

        - `description: string`

        - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

          - `name: string`

          - `type: "url"`

          - `url: string`

        - `model: object { id, speed }`

          Model identifier and configuration.

          - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

            The model that will power your agent.

            See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

          - `speed: optional "standard" or "fast"`

            Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `name: string`

        - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

          - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

            A resolved Anthropic-managed skill.

            - `skill_id: string`

            - `type: "anthropic"`

              - `"anthropic"`

            - `version: string`

          - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

            A resolved user-created custom skill.

            - `skill_id: string`

            - `type: "custom"`

              - `"custom"`

            - `version: string`

        - `system: string`

        - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

          - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

            - `configs: array of BetaManagedAgentsAgentToolConfig`

              - `enabled: boolean`

              - `name: "bash" or "edit" or "read" or 5 more`

                Built-in agent tool identifier.

                - `"bash"`

                - `"edit"`

                - `"read"`

                - `"write"`

                - `"glob"`

                - `"grep"`

                - `"web_fetch"`

                - `"web_search"`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                  - `type: "always_allow"`

                    - `"always_allow"`

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

                  - `type: "always_ask"`

                    - `"always_ask"`

            - `default_config: object { enabled, permission_policy }`

              Resolved default configuration for agent tools.

              - `enabled: boolean`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

            - `type: "agent_toolset_20260401"`

              - `"agent_toolset_20260401"`

          - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

            - `configs: array of BetaManagedAgentsMCPToolConfig`

              - `enabled: boolean`

              - `name: string`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

            - `default_config: object { enabled, permission_policy }`

              Resolved default configuration for all tools from an MCP server.

              - `enabled: boolean`

              - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                Permission policy for tool execution.

                - `beta_managed_agents_always_allow_policy: object { type }`

                  Tool calls are automatically approved without user confirmation.

                - `beta_managed_agents_always_ask_policy: object { type }`

                  Tool calls require user confirmation before execution.

            - `mcp_server_name: string`

            - `type: "mcp_toolset"`

              - `"mcp_toolset"`

          - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

            A custom tool as returned in API responses.

            - `description: string`

            - `input_schema: object { type, properties, required }`

              JSON Schema for custom tool input parameters.

              - `type: "object"`

              - `properties: optional map[unknown]`

              - `required: optional array of string`

            - `name: string`

            - `type: "custom"`

              - `"custom"`

        - `type: "agent"`

          - `"agent"`

        - `version: number`

      - `type: "coordinator"`

        - `"coordinator"`

    - `name: string`

    - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

      - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

        A resolved Anthropic-managed skill.

      - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

        A resolved user-created custom skill.

    - `system: string`

    - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

      - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

      - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

      - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

        A custom tool as returned in API responses.

    - `type: "agent"`

      - `"agent"`

    - `version: number`

  - `metadata: optional map[string]`

    The session's full metadata bag after the update. Present when the update set non-empty metadata; absent when metadata was unchanged or cleared to empty.

  - `title: optional string`

    The session's new title. Present only when the update changed it.

### Beta Managed Agents Session Usage

- `beta_managed_agents_session_usage: object { cache_creation, cache_read_input_tokens, input_tokens, output_tokens }`

  Cumulative token usage for a session across all turns.

  - `cache_creation: optional object { ephemeral_1h_input_tokens, ephemeral_5m_input_tokens }`

    Prompt-cache creation token usage broken down by cache lifetime.

    - `ephemeral_1h_input_tokens: optional number`

      Tokens used to create 1-hour ephemeral cache entries.

    - `ephemeral_5m_input_tokens: optional number`

      Tokens used to create 5-minute ephemeral cache entries.

  - `cache_read_input_tokens: optional number`

    Total tokens read from prompt cache.

  - `input_tokens: optional number`

    Total input tokens consumed across all turns.

  - `output_tokens: optional number`

    Total output tokens generated across all turns.

### Beta Managed Agents System Content Block

- `beta_managed_agents_system_content_block: object { text, type }`

  Regular text content.

  - `text: string`

    The text content.

  - `type: "text"`

    - `"text"`

### Beta Managed Agents System Message Event

- `beta_managed_agents_system_message_event: object { id, content, type, processed_at }`

  A mid-conversation system message event. Carries system-role content that is appended to the session as a `role: "system"` turn.

  - `id: string`

    Unique identifier for this event.

  - `content: array of BetaManagedAgentsSystemContentBlock`

    System content blocks. Text-only.

    - `text: string`

      The text content.

    - `type: "text"`

      - `"text"`

  - `type: "system.message"`

    - `"system.message"`

  - `processed_at: optional string`

    A timestamp in RFC 3339 format

### Beta Managed Agents User Tool Result Event

- `beta_managed_agents_user_tool_result_event: object { id, tool_use_id, type, 4 more }`

  Event sent by the client providing the result of an agent-toolset tool execution. Only valid on `self_hosted` environments, where sandbox-routed tools are executed by the client rather than the server.

  - `id: string`

    Unique identifier for this event.

  - `tool_use_id: string`

    The id of the `agent.tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

  - `type: "user.tool_result"`

    - `"user.tool_result"`

  - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

    The result content returned by the tool.

    - `beta_managed_agents_text_block: object { text, type }`

      Regular text content.

      - `text: string`

        The text content.

      - `type: "text"`

        - `"text"`

    - `beta_managed_agents_image_block: object { source, type }`

      Image content specified directly as base64 data or as a reference via a URL.

      - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

        Union type for image source variants.

        - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

          Base64-encoded image data.

          - `data: string`

            Base64-encoded image data.

          - `media_type: string`

            MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_url_image_source: object { type, url }`

          Image referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the image to fetch.

        - `beta_managed_agents_file_image_source: object { file_id, type }`

          Image referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "image"`

        - `"image"`

    - `beta_managed_agents_document_block: object { source, type, context, title }`

      Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

        Union type for document source variants.

        - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

          Base64-encoded document data.

          - `data: string`

            Base64-encoded document data.

          - `media_type: string`

            MIME type of the document (e.g., "application/pdf").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

          Plain text document content.

          - `data: string`

            The plain text content.

          - `media_type: "text/plain"`

            MIME type of the text content. Must be "text/plain".

            - `"text/plain"`

          - `type: "text"`

            - `"text"`

        - `beta_managed_agents_url_document_source: object { type, url }`

          Document referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the document to fetch.

        - `beta_managed_agents_file_document_source: object { file_id, type }`

          Document referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "document"`

        - `"document"`

      - `context: optional string`

        Additional context about the document for the model.

      - `title: optional string`

        The title of the document.

    - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

      A block containing a web search result.

      - `citations: object { enabled }`

        Citation settings for a search result.

        - `enabled: boolean`

          Whether citations are enabled for this search result.

      - `content: array of BetaManagedAgentsSearchResultContent`

        Array of text content blocks from the search result.

        - `text: string`

          The text content.

        - `type: "text"`

          - `"text"`

      - `source: string`

        The URL source of the search result.

      - `title: string`

        The title of the search result.

      - `type: "search_result"`

        - `"search_result"`

  - `is_error: optional boolean`

    Whether the tool execution resulted in an error.

  - `processed_at: optional string`

    A timestamp in RFC 3339 format

  - `session_thread_id: optional string`

    Routes this result to a subagent thread. Copy from the `agent.tool_use` event's `session_thread_id`.

# Events

## List Events

`$ ant beta:sessions:events list`

**get** `/v1/sessions/{session_id}/events`

List Events

### Parameters

- `--session-id: string`

  Path param: Path parameter session_id

- `--created-at-gt: optional string`

  Query param: Return events created after this time (exclusive).

- `--created-at-gte: optional string`

  Query param: Return events created at or after this time (inclusive).

- `--created-at-lt: optional string`

  Query param: Return events created before this time (exclusive).

- `--created-at-lte: optional string`

  Query param: Return events created at or before this time (inclusive).

- `--limit: optional number`

  Query param: Query parameter for limit

- `--order: optional "asc" or "desc"`

  Query param: Sort direction for results, ordered by created_at. Defaults to asc (chronological).

- `--page: optional string`

  Query param: Opaque pagination cursor from a previous response's next_page.

- `--type: optional array of string`

  Query param: Filter by event type. Values match the `type` field on returned events (for example, `user.message` or `agent.tool_use`). Omit to return all event types.

- `--beta: optional array of AnthropicBeta`

  Header param: Optional header to specify the beta version(s) you want to use.

### Returns

- `BetaManagedAgentsListSessionEvents: object { data, next_page }`

  Paginated list of events for a `session`.

  - `data: optional array of BetaManagedAgentsSessionEvent`

    Events for the session, ordered by `created_at`.

    - `beta_managed_agents_user_message_event: object { id, content, type, processed_at }`

      A user message event in the session conversation.

      - `id: string`

        Unique identifier for this event.

      - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

        Array of content blocks comprising the user message.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

          - `text: string`

            The text content.

          - `type: "text"`

            - `"text"`

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

          - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

            Union type for image source variants.

            - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

              Base64-encoded image data.

              - `data: string`

                Base64-encoded image data.

              - `media_type: string`

                MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

              - `type: "base64"`

                - `"base64"`

            - `beta_managed_agents_url_image_source: object { type, url }`

              Image referenced by URL.

              - `type: "url"`

                - `"url"`

              - `url: string`

                URL of the image to fetch.

            - `beta_managed_agents_file_image_source: object { file_id, type }`

              Image referenced by file ID.

              - `file_id: string`

                ID of a previously uploaded file.

              - `type: "file"`

                - `"file"`

          - `type: "image"`

            - `"image"`

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

          - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

            Union type for document source variants.

            - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

              Base64-encoded document data.

              - `data: string`

                Base64-encoded document data.

              - `media_type: string`

                MIME type of the document (e.g., "application/pdf").

              - `type: "base64"`

                - `"base64"`

            - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

              Plain text document content.

              - `data: string`

                The plain text content.

              - `media_type: "text/plain"`

                MIME type of the text content. Must be "text/plain".

                - `"text/plain"`

              - `type: "text"`

                - `"text"`

            - `beta_managed_agents_url_document_source: object { type, url }`

              Document referenced by URL.

              - `type: "url"`

                - `"url"`

              - `url: string`

                URL of the document to fetch.

            - `beta_managed_agents_file_document_source: object { file_id, type }`

              Document referenced by file ID.

              - `file_id: string`

                ID of a previously uploaded file.

              - `type: "file"`

                - `"file"`

          - `type: "document"`

            - `"document"`

          - `context: optional string`

            Additional context about the document for the model.

          - `title: optional string`

            The title of the document.

      - `type: "user.message"`

        - `"user.message"`

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

    - `beta_managed_agents_user_interrupt_event: object { id, type, processed_at, session_thread_id }`

      An interrupt event that pauses agent execution and returns control to the user.

      - `id: string`

        Unique identifier for this event.

      - `type: "user.interrupt"`

        - `"user.interrupt"`

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

      - `session_thread_id: optional string`

        If absent, interrupts every non-archived thread in a multiagent session (or the primary alone in a single-agent session). If present, interrupts only the named thread.

    - `beta_managed_agents_user_tool_confirmation_event: object { id, result, tool_use_id, 4 more }`

      A tool confirmation event that approves or denies a pending tool execution.

      - `id: string`

        Unique identifier for this event.

      - `result: "allow" or "deny"`

        UserToolConfirmationResult enum

        - `"allow"`

        - `"deny"`

      - `tool_use_id: string`

        The id of the `agent.tool_use` or `agent.mcp_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

      - `type: "user.tool_confirmation"`

        - `"user.tool_confirmation"`

      - `deny_message: optional string`

        Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'.

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

      - `session_thread_id: optional string`

        When set, the confirmation routes to this subagent's thread rather than the primary. Echo this from the `session_thread_id` on the `agent.tool_use` or `agent.mcp_tool_use` event that prompted the approval.

    - `beta_managed_agents_user_custom_tool_result_event: object { id, custom_tool_use_id, type, 4 more }`

      Event sent by the client providing the result of a custom tool execution.

      - `id: string`

        Unique identifier for this event.

      - `custom_tool_use_id: string`

        The id of the `agent.custom_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

      - `type: "user.custom_tool_result"`

        - `"user.custom_tool_result"`

      - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

        The result content returned by the tool.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

          A block containing a web search result.

          - `citations: object { enabled }`

            Citation settings for a search result.

            - `enabled: boolean`

              Whether citations are enabled for this search result.

          - `content: array of BetaManagedAgentsSearchResultContent`

            Array of text content blocks from the search result.

            - `text: string`

              The text content.

            - `type: "text"`

              - `"text"`

          - `source: string`

            The URL source of the search result.

          - `title: string`

            The title of the search result.

          - `type: "search_result"`

            - `"search_result"`

      - `is_error: optional boolean`

        Whether the tool execution resulted in an error.

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

      - `session_thread_id: optional string`

        Routes this result to a subagent thread. Copy from the `agent.custom_tool_use` event's `session_thread_id`.

    - `beta_managed_agents_agent_custom_tool_use_event: object { id, input, name, 3 more }`

      Event emitted when the agent calls a custom tool. The session goes idle until the client sends a `user.custom_tool_result` event with the result.

      - `id: string`

        Unique identifier for this event.

      - `input: map[unknown]`

        Input parameters for the tool call.

      - `name: string`

        Name of the custom tool being called.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "agent.custom_tool_use"`

        - `"agent.custom_tool_use"`

      - `session_thread_id: optional string`

        When set, this event was cross-posted from a subagent's thread to surface its custom tool use on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.custom_tool_result` event to route the result back.

    - `beta_managed_agents_agent_message_event: object { id, content, processed_at, type }`

      An agent response event in the session conversation.

      - `id: string`

        Unique identifier for this event.

      - `content: array of BetaManagedAgentsTextBlock`

        Array of text blocks comprising the agent response.

        - `text: string`

          The text content.

        - `type: "text"`

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "agent.message"`

        - `"agent.message"`

    - `beta_managed_agents_agent_thinking_event: object { id, processed_at, type }`

      Indicates the agent is making forward progress via extended thinking. A progress signal, not a content carrier.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "agent.thinking"`

        - `"agent.thinking"`

    - `beta_managed_agents_agent_mcp_tool_use_event: object { id, input, mcp_server_name, 5 more }`

      Event emitted when the agent invokes a tool provided by an MCP server.

      - `id: string`

        Unique identifier for this event.

      - `input: map[unknown]`

        Input parameters for the tool call.

      - `mcp_server_name: string`

        Name of the MCP server providing the tool.

      - `name: string`

        Name of the MCP tool being used.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "agent.mcp_tool_use"`

        - `"agent.mcp_tool_use"`

      - `evaluated_permission: optional "allow" or "ask" or "deny"`

        AgentEvaluatedPermission enum

        - `"allow"`

        - `"ask"`

        - `"deny"`

      - `session_thread_id: optional string`

        When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

    - `beta_managed_agents_agent_mcp_tool_result_event: object { id, mcp_tool_use_id, processed_at, 3 more }`

      Event representing the result of an MCP tool execution.

      - `id: string`

        Unique identifier for this event.

      - `mcp_tool_use_id: string`

        The id of the `agent.mcp_tool_use` event this result corresponds to.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "agent.mcp_tool_result"`

        - `"agent.mcp_tool_result"`

      - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

        The result content returned by the tool.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

          A block containing a web search result.

      - `is_error: optional boolean`

        Whether the tool execution resulted in an error.

    - `beta_managed_agents_agent_tool_use_event: object { id, input, name, 4 more }`

      Event emitted when the agent invokes a built-in agent tool.

      - `id: string`

        Unique identifier for this event.

      - `input: map[unknown]`

        Input parameters for the tool call.

      - `name: string`

        Name of the agent tool being used.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "agent.tool_use"`

        - `"agent.tool_use"`

      - `evaluated_permission: optional "allow" or "ask" or "deny"`

        AgentEvaluatedPermission enum

        - `"allow"`

        - `"ask"`

        - `"deny"`

      - `session_thread_id: optional string`

        When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

    - `beta_managed_agents_agent_tool_result_event: object { id, processed_at, tool_use_id, 3 more }`

      Event representing the result of an agent tool execution.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `tool_use_id: string`

        The id of the `agent.tool_use` event this result corresponds to.

      - `type: "agent.tool_result"`

        - `"agent.tool_result"`

      - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

        The result content returned by the tool.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

          A block containing a web search result.

      - `is_error: optional boolean`

        Whether the tool execution resulted in an error.

    - `beta_managed_agents_agent_thread_message_received_event: object { id, content, from_session_thread_id, 3 more }`

      Delivery event written to the target thread's input stream when an agent-to-agent message arrives.

      - `id: string`

        Unique identifier for this event.

      - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

        Message content blocks.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `from_session_thread_id: string`

        Public `sthr_` ID of the thread that sent the message.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "agent.thread_message_received"`

        - `"agent.thread_message_received"`

      - `from_agent_name: optional string`

        Name of the callable agent this message came from. Absent when received from the primary agent.

    - `beta_managed_agents_agent_thread_message_sent_event: object { id, content, processed_at, 3 more }`

      Observability event emitted to the sender's output stream when an agent-to-agent message is sent.

      - `id: string`

        Unique identifier for this event.

      - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

        Message content blocks.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `to_session_thread_id: string`

        Public `sthr_` ID of the thread the message was sent to.

      - `type: "agent.thread_message_sent"`

        - `"agent.thread_message_sent"`

      - `to_agent_name: optional string`

        Name of the callable agent this message was sent to. Absent when sent to the primary agent.

    - `beta_managed_agents_agent_thread_context_compacted_event: object { id, processed_at, type }`

      Indicates that context compaction (summarization) occurred during the session.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "agent.thread_context_compacted"`

        - `"agent.thread_context_compacted"`

    - `beta_managed_agents_session_error_event: object { id, error, processed_at, type }`

      An error event indicating a problem occurred during session execution.

      - `id: string`

        Unique identifier for this event.

      - `error: BetaManagedAgentsUnknownError or BetaManagedAgentsModelOverloadedError or BetaManagedAgentsModelRateLimitedError or 5 more`

        An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

        - `beta_managed_agents_unknown_error: object { message, retry_status, type }`

          An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

          - `message: string`

            Human-readable error description.

          - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

            What the client should do next in response to this error.

            - `beta_managed_agents_retry_status_retrying: object { type }`

              The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

              - `type: "retrying"`

                - `"retrying"`

            - `beta_managed_agents_retry_status_exhausted: object { type }`

              This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

              - `type: "exhausted"`

                - `"exhausted"`

            - `beta_managed_agents_retry_status_terminal: object { type }`

              The session encountered a terminal error and will transition to `terminated` state.

              - `type: "terminal"`

                - `"terminal"`

          - `type: "unknown_error"`

            - `"unknown_error"`

        - `beta_managed_agents_model_overloaded_error: object { message, retry_status, type }`

          The model is currently overloaded. Emitted after automatic retries are exhausted.

          - `message: string`

            Human-readable error description.

          - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

            What the client should do next in response to this error.

            - `beta_managed_agents_retry_status_retrying: object { type }`

              The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `beta_managed_agents_retry_status_exhausted: object { type }`

              This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `beta_managed_agents_retry_status_terminal: object { type }`

              The session encountered a terminal error and will transition to `terminated` state.

          - `type: "model_overloaded_error"`

            - `"model_overloaded_error"`

        - `beta_managed_agents_model_rate_limited_error: object { message, retry_status, type }`

          The model request was rate-limited.

          - `message: string`

            Human-readable error description.

          - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

            What the client should do next in response to this error.

            - `beta_managed_agents_retry_status_retrying: object { type }`

              The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `beta_managed_agents_retry_status_exhausted: object { type }`

              This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `beta_managed_agents_retry_status_terminal: object { type }`

              The session encountered a terminal error and will transition to `terminated` state.

          - `type: "model_rate_limited_error"`

            - `"model_rate_limited_error"`

        - `beta_managed_agents_model_request_failed_error: object { message, retry_status, type }`

          A model request failed for a reason other than overload or rate-limiting.

          - `message: string`

            Human-readable error description.

          - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

            What the client should do next in response to this error.

            - `beta_managed_agents_retry_status_retrying: object { type }`

              The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `beta_managed_agents_retry_status_exhausted: object { type }`

              This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `beta_managed_agents_retry_status_terminal: object { type }`

              The session encountered a terminal error and will transition to `terminated` state.

          - `type: "model_request_failed_error"`

            - `"model_request_failed_error"`

        - `beta_managed_agents_mcp_connection_failed_error: object { mcp_server_name, message, retry_status, type }`

          Failed to connect to an MCP server.

          - `mcp_server_name: string`

            Name of the MCP server that failed to connect.

          - `message: string`

            Human-readable error description.

          - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

            What the client should do next in response to this error.

            - `beta_managed_agents_retry_status_retrying: object { type }`

              The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `beta_managed_agents_retry_status_exhausted: object { type }`

              This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `beta_managed_agents_retry_status_terminal: object { type }`

              The session encountered a terminal error and will transition to `terminated` state.

          - `type: "mcp_connection_failed_error"`

            - `"mcp_connection_failed_error"`

        - `beta_managed_agents_mcp_authentication_failed_error: object { mcp_server_name, message, retry_status, type }`

          Authentication to an MCP server failed.

          - `mcp_server_name: string`

            Name of the MCP server that failed authentication.

          - `message: string`

            Human-readable error description.

          - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

            What the client should do next in response to this error.

            - `beta_managed_agents_retry_status_retrying: object { type }`

              The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `beta_managed_agents_retry_status_exhausted: object { type }`

              This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `beta_managed_agents_retry_status_terminal: object { type }`

              The session encountered a terminal error and will transition to `terminated` state.

          - `type: "mcp_authentication_failed_error"`

            - `"mcp_authentication_failed_error"`

        - `beta_managed_agents_billing_error: object { message, retry_status, type }`

          The caller's organization or workspace cannot make model requests — out of credits or spend limit reached. Retrying with the same credentials will not succeed; the caller must resolve the billing state.

          - `message: string`

            Human-readable error description.

          - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

            What the client should do next in response to this error.

            - `beta_managed_agents_retry_status_retrying: object { type }`

              The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `beta_managed_agents_retry_status_exhausted: object { type }`

              This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `beta_managed_agents_retry_status_terminal: object { type }`

              The session encountered a terminal error and will transition to `terminated` state.

          - `type: "billing_error"`

            - `"billing_error"`

        - `beta_managed_agents_credential_host_unreachable_error: object { credential_id, message, retry_status, 2 more }`

          An `environment_variable` credential's `auth.networking.allowed_hosts` includes a host the environment's network policy does not permit.

          - `credential_id: string`

            ID of the affected credential.

          - `message: string`

            Human-readable error description.

          - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

            What the client should do next in response to this error.

            - `beta_managed_agents_retry_status_retrying: object { type }`

              The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `beta_managed_agents_retry_status_exhausted: object { type }`

              This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `beta_managed_agents_retry_status_terminal: object { type }`

              The session encountered a terminal error and will transition to `terminated` state.

          - `type: "credential_host_unreachable_error"`

            - `"credential_host_unreachable_error"`

          - `vault_id: string`

            ID of the vault containing the affected credential.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "session.error"`

        - `"session.error"`

    - `beta_managed_agents_session_status_rescheduled_event: object { id, processed_at, type }`

      Indicates the session is recovering from an error state and is rescheduled for execution.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "session.status_rescheduled"`

        - `"session.status_rescheduled"`

    - `beta_managed_agents_session_status_running_event: object { id, processed_at, type }`

      Indicates the session is actively running and the agent is working.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "session.status_running"`

        - `"session.status_running"`

    - `beta_managed_agents_session_status_idle_event: object { id, processed_at, stop_reason, type }`

      Indicates the agent has paused and is awaiting user input.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `stop_reason: BetaManagedAgentsSessionEndTurn or BetaManagedAgentsSessionRequiresAction or BetaManagedAgentsSessionRetriesExhausted`

        The agent completed its turn naturally and is ready for the next user message.

        - `beta_managed_agents_session_end_turn: object { type }`

          The agent completed its turn naturally and is ready for the next user message.

          - `type: "end_turn"`

            - `"end_turn"`

        - `beta_managed_agents_session_requires_action: object { event_ids, type }`

          The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

          - `event_ids: array of string`

            The ids of events the agent is blocked on. Resolving fewer than all re-emits `session.status_idle` with the remainder.

          - `type: "requires_action"`

            - `"requires_action"`

        - `beta_managed_agents_session_retries_exhausted: object { type }`

          The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

          - `type: "retries_exhausted"`

            - `"retries_exhausted"`

      - `type: "session.status_idle"`

        - `"session.status_idle"`

    - `beta_managed_agents_session_status_terminated_event: object { id, processed_at, type }`

      Indicates the session has terminated, either due to an error or completion.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "session.status_terminated"`

        - `"session.status_terminated"`

    - `beta_managed_agents_session_thread_created_event: object { id, agent_name, processed_at, 2 more }`

      Emitted when a subagent is spawned as a new thread. Written to the parent thread's output stream so clients observing the session see child creation.

      - `id: string`

        Unique identifier for this event.

      - `agent_name: string`

        Name of the callable agent the thread runs.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `session_thread_id: string`

        Public `sthr_` ID of the newly created thread.

      - `type: "session.thread_created"`

        - `"session.thread_created"`

    - `beta_managed_agents_span_outcome_evaluation_start_event: object { id, iteration, outcome_id, 2 more }`

      Emitted when an outcome evaluation cycle begins.

      - `id: string`

        Unique identifier for this event.

      - `iteration: number`

        0-indexed revision cycle. 0 is the first evaluation; 1 is the re-evaluation after the first revision; etc.

      - `outcome_id: string`

        The `outc_` ID of the outcome being evaluated.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "span.outcome_evaluation_start"`

        - `"span.outcome_evaluation_start"`

    - `beta_managed_agents_span_outcome_evaluation_end_event: object { id, explanation, iteration, 6 more }`

      Emitted when an outcome evaluation cycle completes. Carries the verdict and aggregate token usage. A verdict of `needs_revision` means another evaluation cycle follows; `satisfied`, `max_iterations_reached`, `failed`, or `interrupted` are terminal — no further evaluation cycles follow.

      - `id: string`

        Unique identifier for this event.

      - `explanation: string`

        Human-readable explanation of the verdict. For `needs_revision`, describes which criteria failed and why.

      - `iteration: number`

        0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

      - `outcome_evaluation_start_id: string`

        The id of the corresponding `span.outcome_evaluation_start` event.

      - `outcome_id: string`

        The `outc_` ID of the outcome being evaluated.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `result: string`

        Evaluation verdict. 'satisfied': criteria met, session goes idle. 'needs_revision': criteria not met, another revision cycle follows. 'max_iterations_reached': evaluation budget exhausted with criteria still unmet — one final acknowledgment turn follows before the session goes idle, but no further evaluation runs. 'failed': grader determined the rubric does not apply to the deliverables. 'interrupted': user sent an interrupt while evaluation was in progress.

      - `type: "span.outcome_evaluation_end"`

        - `"span.outcome_evaluation_end"`

      - `usage: object { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }`

        Token usage for a single model request.

        - `cache_creation_input_tokens: number`

          Tokens used to create prompt cache in this request.

        - `cache_read_input_tokens: number`

          Tokens read from prompt cache in this request.

        - `input_tokens: number`

          Input tokens consumed by this request.

        - `output_tokens: number`

          Output tokens generated by this request.

        - `speed: optional "standard" or "fast"`

          Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

          - `"standard"`

          - `"fast"`

    - `beta_managed_agents_span_model_request_start_event: object { id, processed_at, type }`

      Emitted when a model request is initiated by the agent.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "span.model_request_start"`

        - `"span.model_request_start"`

    - `beta_managed_agents_span_model_request_end_event: object { id, is_error, model_request_start_id, 3 more }`

      Emitted when a model request completes.

      - `id: string`

        Unique identifier for this event.

      - `is_error: boolean`

        Whether the model request resulted in an error.

      - `model_request_start_id: string`

        The id of the corresponding `span.model_request_start` event.

      - `model_usage: object { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }`

        Token usage for a single model request.

        - `cache_creation_input_tokens: number`

          Tokens used to create prompt cache in this request.

        - `cache_read_input_tokens: number`

          Tokens read from prompt cache in this request.

        - `input_tokens: number`

          Input tokens consumed by this request.

        - `output_tokens: number`

          Output tokens generated by this request.

        - `speed: optional "standard" or "fast"`

          Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "span.model_request_end"`

        - `"span.model_request_end"`

    - `beta_managed_agents_span_outcome_evaluation_ongoing_event: object { id, iteration, outcome_id, 2 more }`

      Periodic heartbeat emitted while an outcome evaluation cycle is in progress. Distinguishes 'evaluation is actively running' from 'evaluation is stuck' between the corresponding `span.outcome_evaluation_start` and `span.outcome_evaluation_end` events.

      - `id: string`

        Unique identifier for this event.

      - `iteration: number`

        0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

      - `outcome_id: string`

        The `outc_` ID of the outcome being evaluated.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "span.outcome_evaluation_ongoing"`

        - `"span.outcome_evaluation_ongoing"`

    - `beta_managed_agents_user_define_outcome_event: object { id, description, max_iterations, 4 more }`

      Echo of a `user.define_outcome` input event. Carries the server-generated `outcome_id` that subsequent `span.outcome_evaluation_*` events reference.

      - `id: string`

        Unique identifier for this event.

      - `description: string`

        What the agent should produce. Copied from the input event.

      - `max_iterations: number`

        Evaluate-then-revise cycles before giving up. Default 3, max 20.

      - `outcome_id: string`

        Server-generated `outc_` ID for this outcome. Referenced by `span.outcome_evaluation_*` events and the session's `outcome_evaluations` list.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `rubric: BetaManagedAgentsFileRubric or BetaManagedAgentsTextRubric`

        Rubric for grading the quality of an outcome.

        - `beta_managed_agents_file_rubric: object { file_id, type }`

          Rubric referenced by a file uploaded via the Files API.

          - `file_id: string`

            ID of the rubric file.

          - `type: "file"`

            - `"file"`

        - `beta_managed_agents_text_rubric: object { content, type }`

          Rubric content provided inline as text.

          - `content: string`

            Rubric content. Plain text or markdown — the grader treats it as freeform text.

          - `type: "text"`

            - `"text"`

      - `type: "user.define_outcome"`

        - `"user.define_outcome"`

    - `beta_managed_agents_session_deleted_event: object { id, processed_at, type }`

      Emitted when a session has been deleted. Terminates any active event stream — no further events will be emitted for this session.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "session.deleted"`

        - `"session.deleted"`

    - `beta_managed_agents_session_thread_status_running_event: object { id, agent_name, processed_at, 2 more }`

      A session thread has begun executing. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

      - `id: string`

        Unique identifier for this event.

      - `agent_name: string`

        Name of the agent the thread runs.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `session_thread_id: string`

        Public sthr_ ID of the thread that started running.

      - `type: "session.thread_status_running"`

        - `"session.thread_status_running"`

    - `beta_managed_agents_session_thread_status_idle_event: object { id, agent_name, processed_at, 3 more }`

      A session thread has yielded and is awaiting input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

      - `id: string`

        Unique identifier for this event.

      - `agent_name: string`

        Name of the agent the thread runs.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `session_thread_id: string`

        Public sthr_ ID of the thread that went idle.

      - `stop_reason: BetaManagedAgentsSessionEndTurn or BetaManagedAgentsSessionRequiresAction or BetaManagedAgentsSessionRetriesExhausted`

        The agent completed its turn naturally and is ready for the next user message.

        - `beta_managed_agents_session_end_turn: object { type }`

          The agent completed its turn naturally and is ready for the next user message.

        - `beta_managed_agents_session_requires_action: object { event_ids, type }`

          The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

        - `beta_managed_agents_session_retries_exhausted: object { type }`

          The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

      - `type: "session.thread_status_idle"`

        - `"session.thread_status_idle"`

    - `beta_managed_agents_session_thread_status_terminated_event: object { id, agent_name, processed_at, 2 more }`

      A session thread has terminated and will accept no further input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

      - `id: string`

        Unique identifier for this event.

      - `agent_name: string`

        Name of the agent the thread runs.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `session_thread_id: string`

        Public sthr_ ID of the thread that terminated.

      - `type: "session.thread_status_terminated"`

        - `"session.thread_status_terminated"`

    - `beta_managed_agents_user_tool_result_event: object { id, tool_use_id, type, 4 more }`

      Event sent by the client providing the result of an agent-toolset tool execution. Only valid on `self_hosted` environments, where sandbox-routed tools are executed by the client rather than the server.

      - `id: string`

        Unique identifier for this event.

      - `tool_use_id: string`

        The id of the `agent.tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

      - `type: "user.tool_result"`

        - `"user.tool_result"`

      - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

        The result content returned by the tool.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

          A block containing a web search result.

      - `is_error: optional boolean`

        Whether the tool execution resulted in an error.

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

      - `session_thread_id: optional string`

        Routes this result to a subagent thread. Copy from the `agent.tool_use` event's `session_thread_id`.

    - `beta_managed_agents_session_thread_status_rescheduled_event: object { id, agent_name, processed_at, 2 more }`

      A session thread hit a transient error and is retrying automatically. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

      - `id: string`

        Unique identifier for this event.

      - `agent_name: string`

        Name of the agent the thread runs.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `session_thread_id: string`

        Public sthr_ ID of the thread that is retrying.

      - `type: "session.thread_status_rescheduled"`

        - `"session.thread_status_rescheduled"`

    - `beta_managed_agents_session_updated_event: object { id, processed_at, type, 3 more }`

      Emitted when an UpdateSession request changed at least one field. Carries only the fields that changed; absent fields were not part of the update. The new configuration applies from the next turn.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "session.updated"`

        - `"session.updated"`

      - `agent: optional object { id, description, mcp_servers, 8 more }`

        Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time.

        - `id: string`

        - `description: string`

        - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

          - `name: string`

          - `type: "url"`

            - `"url"`

          - `url: string`

        - `model: object { id, speed }`

          Model identifier and configuration.

          - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

            The model that will power your agent.

            See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

            - `"claude-fable-5"`

              Next generation of intelligence for the hardest knowledge work and coding problems

            - `"claude-opus-4-8"`

              Frontier intelligence for long-running agents and coding

            - `"claude-opus-4-7"`

              Frontier intelligence for long-running agents and coding

            - `"claude-opus-4-6"`

              Most intelligent model for building agents and coding

            - `"claude-sonnet-4-6"`

              Best combination of speed and intelligence

            - `"claude-haiku-4-5"`

              Fastest model with near-frontier intelligence

            - `"claude-haiku-4-5-20251001"`

              Fastest model with near-frontier intelligence

            - `"claude-opus-4-5"`

              Premium model combining maximum intelligence with practical performance

            - `"claude-opus-4-5-20251101"`

              Premium model combining maximum intelligence with practical performance

            - `"claude-sonnet-4-5"`

              High-performance model for agents and coding

            - `"claude-sonnet-4-5-20250929"`

              High-performance model for agents and coding

          - `speed: optional "standard" or "fast"`

            Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

            - `"standard"`

            - `"fast"`

        - `multiagent: object { agents, type }`

          Resolved coordinator topology with full agent definitions for each roster member.

          - `agents: array of BetaManagedAgentsSessionThreadAgent`

            Full `agent` definitions the coordinator may spawn as session threads.

            - `id: string`

            - `description: string`

            - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

              - `name: string`

              - `type: "url"`

              - `url: string`

            - `model: object { id, speed }`

              Model identifier and configuration.

              - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

                The model that will power your agent.

                See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

              - `speed: optional "standard" or "fast"`

                Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

            - `name: string`

            - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

              - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

                A resolved Anthropic-managed skill.

                - `skill_id: string`

                - `type: "anthropic"`

                  - `"anthropic"`

                - `version: string`

              - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

                A resolved user-created custom skill.

                - `skill_id: string`

                - `type: "custom"`

                  - `"custom"`

                - `version: string`

            - `system: string`

            - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

              - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

                - `configs: array of BetaManagedAgentsAgentToolConfig`

                  - `enabled: boolean`

                  - `name: "bash" or "edit" or "read" or 5 more`

                    Built-in agent tool identifier.

                    - `"bash"`

                    - `"edit"`

                    - `"read"`

                    - `"write"`

                    - `"glob"`

                    - `"grep"`

                    - `"web_fetch"`

                    - `"web_search"`

                  - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                    Permission policy for tool execution.

                    - `beta_managed_agents_always_allow_policy: object { type }`

                      Tool calls are automatically approved without user confirmation.

                      - `type: "always_allow"`

                        - `"always_allow"`

                    - `beta_managed_agents_always_ask_policy: object { type }`

                      Tool calls require user confirmation before execution.

                      - `type: "always_ask"`

                        - `"always_ask"`

                - `default_config: object { enabled, permission_policy }`

                  Resolved default configuration for agent tools.

                  - `enabled: boolean`

                  - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                    Permission policy for tool execution.

                    - `beta_managed_agents_always_allow_policy: object { type }`

                      Tool calls are automatically approved without user confirmation.

                    - `beta_managed_agents_always_ask_policy: object { type }`

                      Tool calls require user confirmation before execution.

                - `type: "agent_toolset_20260401"`

                  - `"agent_toolset_20260401"`

              - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

                - `configs: array of BetaManagedAgentsMCPToolConfig`

                  - `enabled: boolean`

                  - `name: string`

                  - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                    Permission policy for tool execution.

                    - `beta_managed_agents_always_allow_policy: object { type }`

                      Tool calls are automatically approved without user confirmation.

                    - `beta_managed_agents_always_ask_policy: object { type }`

                      Tool calls require user confirmation before execution.

                - `default_config: object { enabled, permission_policy }`

                  Resolved default configuration for all tools from an MCP server.

                  - `enabled: boolean`

                  - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                    Permission policy for tool execution.

                    - `beta_managed_agents_always_allow_policy: object { type }`

                      Tool calls are automatically approved without user confirmation.

                    - `beta_managed_agents_always_ask_policy: object { type }`

                      Tool calls require user confirmation before execution.

                - `mcp_server_name: string`

                - `type: "mcp_toolset"`

                  - `"mcp_toolset"`

              - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

                A custom tool as returned in API responses.

                - `description: string`

                - `input_schema: object { type, properties, required }`

                  JSON Schema for custom tool input parameters.

                  - `type: "object"`

                  - `properties: optional map[unknown]`

                  - `required: optional array of string`

                - `name: string`

                - `type: "custom"`

                  - `"custom"`

            - `type: "agent"`

              - `"agent"`

            - `version: number`

          - `type: "coordinator"`

            - `"coordinator"`

        - `name: string`

        - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

          - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

            A resolved Anthropic-managed skill.

          - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

            A resolved user-created custom skill.

        - `system: string`

        - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

          - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

          - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

          - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

            A custom tool as returned in API responses.

        - `type: "agent"`

          - `"agent"`

        - `version: number`

      - `metadata: optional map[string]`

        The session's full metadata bag after the update. Present when the update set non-empty metadata; absent when metadata was unchanged or cleared to empty.

      - `title: optional string`

        The session's new title. Present only when the update changed it.

    - `beta_managed_agents_system_message_event: object { id, content, type, processed_at }`

      A mid-conversation system message event. Carries system-role content that is appended to the session as a `role: "system"` turn.

      - `id: string`

        Unique identifier for this event.

      - `content: array of BetaManagedAgentsSystemContentBlock`

        System content blocks. Text-only.

        - `text: string`

          The text content.

        - `type: "text"`

          - `"text"`

      - `type: "system.message"`

        - `"system.message"`

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

  - `next_page: optional string`

    Opaque cursor for the next page. Null when no more results.

### Example

```cli
ant beta:sessions:events list \
  --api-key my-anthropic-api-key \
  --session-id sesn_011CZkZAtmR3yMPDzynEDxu7
```

#### Response

```json
{
  "data": [
    {
      "id": "sevt_011CZkZGOp0iBcp4kaQSihUmy",
      "content": [
        {
          "text": "Where is my order #1234?",
          "type": "text"
        }
      ],
      "type": "user.message",
      "processed_at": "2026-03-15T10:00:00Z"
    },
    {
      "id": "sevt_011CZkZHPq1jCdq5lbRTjiVnz",
      "content": [
        {
          "text": "Let me look up order #1234 for you.",
          "type": "text"
        }
      ],
      "processed_at": "2026-03-15T10:00:00Z",
      "type": "agent.message"
    }
  ],
  "next_page": "page_MjAyNS0wNS0xNFQwMDowMDowMFo="
}
```

## Send Events

`$ ant beta:sessions:events send`

**post** `/v1/sessions/{session_id}/events`

Send Events

### Parameters

- `--session-id: string`

  Path param: Path parameter session_id

- `--event: array of BetaManagedAgentsEventParams`

  Body param: Events to send to the `session`.

- `--beta: optional array of AnthropicBeta`

  Header param: Optional header to specify the beta version(s) you want to use.

### Returns

- `beta_managed_agents_send_session_events: object { data }`

  Events that were successfully sent to the session.

  - `data: optional array of BetaManagedAgentsUserMessageEvent or BetaManagedAgentsUserInterruptEvent or BetaManagedAgentsUserToolConfirmationEvent or 4 more`

    Sent events

    - `beta_managed_agents_user_message_event: object { id, content, type, processed_at }`

      A user message event in the session conversation.

      - `id: string`

        Unique identifier for this event.

      - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

        Array of content blocks comprising the user message.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

          - `text: string`

            The text content.

          - `type: "text"`

            - `"text"`

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

          - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

            Union type for image source variants.

            - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

              Base64-encoded image data.

              - `data: string`

                Base64-encoded image data.

              - `media_type: string`

                MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

              - `type: "base64"`

                - `"base64"`

            - `beta_managed_agents_url_image_source: object { type, url }`

              Image referenced by URL.

              - `type: "url"`

                - `"url"`

              - `url: string`

                URL of the image to fetch.

            - `beta_managed_agents_file_image_source: object { file_id, type }`

              Image referenced by file ID.

              - `file_id: string`

                ID of a previously uploaded file.

              - `type: "file"`

                - `"file"`

          - `type: "image"`

            - `"image"`

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

          - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

            Union type for document source variants.

            - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

              Base64-encoded document data.

              - `data: string`

                Base64-encoded document data.

              - `media_type: string`

                MIME type of the document (e.g., "application/pdf").

              - `type: "base64"`

                - `"base64"`

            - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

              Plain text document content.

              - `data: string`

                The plain text content.

              - `media_type: "text/plain"`

                MIME type of the text content. Must be "text/plain".

                - `"text/plain"`

              - `type: "text"`

                - `"text"`

            - `beta_managed_agents_url_document_source: object { type, url }`

              Document referenced by URL.

              - `type: "url"`

                - `"url"`

              - `url: string`

                URL of the document to fetch.

            - `beta_managed_agents_file_document_source: object { file_id, type }`

              Document referenced by file ID.

              - `file_id: string`

                ID of a previously uploaded file.

              - `type: "file"`

                - `"file"`

          - `type: "document"`

            - `"document"`

          - `context: optional string`

            Additional context about the document for the model.

          - `title: optional string`

            The title of the document.

      - `type: "user.message"`

        - `"user.message"`

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

    - `beta_managed_agents_user_interrupt_event: object { id, type, processed_at, session_thread_id }`

      An interrupt event that pauses agent execution and returns control to the user.

      - `id: string`

        Unique identifier for this event.

      - `type: "user.interrupt"`

        - `"user.interrupt"`

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

      - `session_thread_id: optional string`

        If absent, interrupts every non-archived thread in a multiagent session (or the primary alone in a single-agent session). If present, interrupts only the named thread.

    - `beta_managed_agents_user_tool_confirmation_event: object { id, result, tool_use_id, 4 more }`

      A tool confirmation event that approves or denies a pending tool execution.

      - `id: string`

        Unique identifier for this event.

      - `result: "allow" or "deny"`

        UserToolConfirmationResult enum

        - `"allow"`

        - `"deny"`

      - `tool_use_id: string`

        The id of the `agent.tool_use` or `agent.mcp_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

      - `type: "user.tool_confirmation"`

        - `"user.tool_confirmation"`

      - `deny_message: optional string`

        Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'.

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

      - `session_thread_id: optional string`

        When set, the confirmation routes to this subagent's thread rather than the primary. Echo this from the `session_thread_id` on the `agent.tool_use` or `agent.mcp_tool_use` event that prompted the approval.

    - `beta_managed_agents_user_custom_tool_result_event: object { id, custom_tool_use_id, type, 4 more }`

      Event sent by the client providing the result of a custom tool execution.

      - `id: string`

        Unique identifier for this event.

      - `custom_tool_use_id: string`

        The id of the `agent.custom_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

      - `type: "user.custom_tool_result"`

        - `"user.custom_tool_result"`

      - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

        The result content returned by the tool.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

          A block containing a web search result.

          - `citations: object { enabled }`

            Citation settings for a search result.

            - `enabled: boolean`

              Whether citations are enabled for this search result.

          - `content: array of BetaManagedAgentsSearchResultContent`

            Array of text content blocks from the search result.

            - `text: string`

              The text content.

            - `type: "text"`

              - `"text"`

          - `source: string`

            The URL source of the search result.

          - `title: string`

            The title of the search result.

          - `type: "search_result"`

            - `"search_result"`

      - `is_error: optional boolean`

        Whether the tool execution resulted in an error.

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

      - `session_thread_id: optional string`

        Routes this result to a subagent thread. Copy from the `agent.custom_tool_use` event's `session_thread_id`.

    - `beta_managed_agents_user_define_outcome_event: object { id, description, max_iterations, 4 more }`

      Echo of a `user.define_outcome` input event. Carries the server-generated `outcome_id` that subsequent `span.outcome_evaluation_*` events reference.

      - `id: string`

        Unique identifier for this event.

      - `description: string`

        What the agent should produce. Copied from the input event.

      - `max_iterations: number`

        Evaluate-then-revise cycles before giving up. Default 3, max 20.

      - `outcome_id: string`

        Server-generated `outc_` ID for this outcome. Referenced by `span.outcome_evaluation_*` events and the session's `outcome_evaluations` list.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `rubric: BetaManagedAgentsFileRubric or BetaManagedAgentsTextRubric`

        Rubric for grading the quality of an outcome.

        - `beta_managed_agents_file_rubric: object { file_id, type }`

          Rubric referenced by a file uploaded via the Files API.

          - `file_id: string`

            ID of the rubric file.

          - `type: "file"`

            - `"file"`

        - `beta_managed_agents_text_rubric: object { content, type }`

          Rubric content provided inline as text.

          - `content: string`

            Rubric content. Plain text or markdown — the grader treats it as freeform text.

          - `type: "text"`

            - `"text"`

      - `type: "user.define_outcome"`

        - `"user.define_outcome"`

    - `beta_managed_agents_user_tool_result_event: object { id, tool_use_id, type, 4 more }`

      Event sent by the client providing the result of an agent-toolset tool execution. Only valid on `self_hosted` environments, where sandbox-routed tools are executed by the client rather than the server.

      - `id: string`

        Unique identifier for this event.

      - `tool_use_id: string`

        The id of the `agent.tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

      - `type: "user.tool_result"`

        - `"user.tool_result"`

      - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

        The result content returned by the tool.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

          A block containing a web search result.

      - `is_error: optional boolean`

        Whether the tool execution resulted in an error.

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

      - `session_thread_id: optional string`

        Routes this result to a subagent thread. Copy from the `agent.tool_use` event's `session_thread_id`.

    - `beta_managed_agents_system_message_event: object { id, content, type, processed_at }`

      A mid-conversation system message event. Carries system-role content that is appended to the session as a `role: "system"` turn.

      - `id: string`

        Unique identifier for this event.

      - `content: array of BetaManagedAgentsSystemContentBlock`

        System content blocks. Text-only.

        - `text: string`

          The text content.

        - `type: "text"`

          - `"text"`

      - `type: "system.message"`

        - `"system.message"`

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

### Example

```cli
ant beta:sessions:events send \
  --api-key my-anthropic-api-key \
  --session-id sesn_011CZkZAtmR3yMPDzynEDxu7 \
  --event "{content: [{text: 'Where is my order #1234?', type: text}], type: user.message}"
```

#### Response

```json
{
  "data": [
    {
      "id": "sevt_011CZkZGOp0iBcp4kaQSihUmy",
      "content": [
        {
          "text": "Where is my order #1234?",
          "type": "text"
        }
      ],
      "type": "user.message",
      "processed_at": "2026-03-15T10:00:00Z"
    }
  ]
}
```

## Stream Events

`$ ant beta:sessions:events stream`

**get** `/v1/sessions/{session_id}/events/stream`

Stream Events

### Parameters

- `--session-id: string`

  Path parameter session_id

- `--beta: optional array of AnthropicBeta`

  Optional header to specify the beta version(s) you want to use.

### Returns

- `beta_managed_agents_stream_session_events: BetaManagedAgentsUserMessageEvent or BetaManagedAgentsUserInterruptEvent or BetaManagedAgentsUserToolConfirmationEvent or 31 more`

  Server-sent event in the session stream.

  - `beta_managed_agents_user_message_event: object { id, content, type, processed_at }`

    A user message event in the session conversation.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

      Array of content blocks comprising the user message.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

        - `text: string`

          The text content.

        - `type: "text"`

          - `"text"`

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

        - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

          Union type for image source variants.

          - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

            Base64-encoded image data.

            - `data: string`

              Base64-encoded image data.

            - `media_type: string`

              MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

            - `type: "base64"`

              - `"base64"`

          - `beta_managed_agents_url_image_source: object { type, url }`

            Image referenced by URL.

            - `type: "url"`

              - `"url"`

            - `url: string`

              URL of the image to fetch.

          - `beta_managed_agents_file_image_source: object { file_id, type }`

            Image referenced by file ID.

            - `file_id: string`

              ID of a previously uploaded file.

            - `type: "file"`

              - `"file"`

        - `type: "image"`

          - `"image"`

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

          Union type for document source variants.

          - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

            Base64-encoded document data.

            - `data: string`

              Base64-encoded document data.

            - `media_type: string`

              MIME type of the document (e.g., "application/pdf").

            - `type: "base64"`

              - `"base64"`

          - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

            Plain text document content.

            - `data: string`

              The plain text content.

            - `media_type: "text/plain"`

              MIME type of the text content. Must be "text/plain".

              - `"text/plain"`

            - `type: "text"`

              - `"text"`

          - `beta_managed_agents_url_document_source: object { type, url }`

            Document referenced by URL.

            - `type: "url"`

              - `"url"`

            - `url: string`

              URL of the document to fetch.

          - `beta_managed_agents_file_document_source: object { file_id, type }`

            Document referenced by file ID.

            - `file_id: string`

              ID of a previously uploaded file.

            - `type: "file"`

              - `"file"`

        - `type: "document"`

          - `"document"`

        - `context: optional string`

          Additional context about the document for the model.

        - `title: optional string`

          The title of the document.

    - `type: "user.message"`

      - `"user.message"`

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

  - `beta_managed_agents_user_interrupt_event: object { id, type, processed_at, session_thread_id }`

    An interrupt event that pauses agent execution and returns control to the user.

    - `id: string`

      Unique identifier for this event.

    - `type: "user.interrupt"`

      - `"user.interrupt"`

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      If absent, interrupts every non-archived thread in a multiagent session (or the primary alone in a single-agent session). If present, interrupts only the named thread.

  - `beta_managed_agents_user_tool_confirmation_event: object { id, result, tool_use_id, 4 more }`

    A tool confirmation event that approves or denies a pending tool execution.

    - `id: string`

      Unique identifier for this event.

    - `result: "allow" or "deny"`

      UserToolConfirmationResult enum

      - `"allow"`

      - `"deny"`

    - `tool_use_id: string`

      The id of the `agent.tool_use` or `agent.mcp_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: "user.tool_confirmation"`

      - `"user.tool_confirmation"`

    - `deny_message: optional string`

      Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'.

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      When set, the confirmation routes to this subagent's thread rather than the primary. Echo this from the `session_thread_id` on the `agent.tool_use` or `agent.mcp_tool_use` event that prompted the approval.

  - `beta_managed_agents_user_custom_tool_result_event: object { id, custom_tool_use_id, type, 4 more }`

    Event sent by the client providing the result of a custom tool execution.

    - `id: string`

      Unique identifier for this event.

    - `custom_tool_use_id: string`

      The id of the `agent.custom_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: "user.custom_tool_result"`

      - `"user.custom_tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

        - `citations: object { enabled }`

          Citation settings for a search result.

          - `enabled: boolean`

            Whether citations are enabled for this search result.

        - `content: array of BetaManagedAgentsSearchResultContent`

          Array of text content blocks from the search result.

          - `text: string`

            The text content.

          - `type: "text"`

            - `"text"`

        - `source: string`

          The URL source of the search result.

        - `title: string`

          The title of the search result.

        - `type: "search_result"`

          - `"search_result"`

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      Routes this result to a subagent thread. Copy from the `agent.custom_tool_use` event's `session_thread_id`.

  - `beta_managed_agents_agent_custom_tool_use_event: object { id, input, name, 3 more }`

    Event emitted when the agent calls a custom tool. The session goes idle until the client sends a `user.custom_tool_result` event with the result.

    - `id: string`

      Unique identifier for this event.

    - `input: map[unknown]`

      Input parameters for the tool call.

    - `name: string`

      Name of the custom tool being called.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.custom_tool_use"`

      - `"agent.custom_tool_use"`

    - `session_thread_id: optional string`

      When set, this event was cross-posted from a subagent's thread to surface its custom tool use on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.custom_tool_result` event to route the result back.

  - `beta_managed_agents_agent_message_event: object { id, content, processed_at, type }`

    An agent response event in the session conversation.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock`

      Array of text blocks comprising the agent response.

      - `text: string`

        The text content.

      - `type: "text"`

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.message"`

      - `"agent.message"`

  - `beta_managed_agents_agent_thinking_event: object { id, processed_at, type }`

    Indicates the agent is making forward progress via extended thinking. A progress signal, not a content carrier.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.thinking"`

      - `"agent.thinking"`

  - `beta_managed_agents_agent_mcp_tool_use_event: object { id, input, mcp_server_name, 5 more }`

    Event emitted when the agent invokes a tool provided by an MCP server.

    - `id: string`

      Unique identifier for this event.

    - `input: map[unknown]`

      Input parameters for the tool call.

    - `mcp_server_name: string`

      Name of the MCP server providing the tool.

    - `name: string`

      Name of the MCP tool being used.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.mcp_tool_use"`

      - `"agent.mcp_tool_use"`

    - `evaluated_permission: optional "allow" or "ask" or "deny"`

      AgentEvaluatedPermission enum

      - `"allow"`

      - `"ask"`

      - `"deny"`

    - `session_thread_id: optional string`

      When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

  - `beta_managed_agents_agent_mcp_tool_result_event: object { id, mcp_tool_use_id, processed_at, 3 more }`

    Event representing the result of an MCP tool execution.

    - `id: string`

      Unique identifier for this event.

    - `mcp_tool_use_id: string`

      The id of the `agent.mcp_tool_use` event this result corresponds to.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.mcp_tool_result"`

      - `"agent.mcp_tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

  - `beta_managed_agents_agent_tool_use_event: object { id, input, name, 4 more }`

    Event emitted when the agent invokes a built-in agent tool.

    - `id: string`

      Unique identifier for this event.

    - `input: map[unknown]`

      Input parameters for the tool call.

    - `name: string`

      Name of the agent tool being used.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.tool_use"`

      - `"agent.tool_use"`

    - `evaluated_permission: optional "allow" or "ask" or "deny"`

      AgentEvaluatedPermission enum

      - `"allow"`

      - `"ask"`

      - `"deny"`

    - `session_thread_id: optional string`

      When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

  - `beta_managed_agents_agent_tool_result_event: object { id, processed_at, tool_use_id, 3 more }`

    Event representing the result of an agent tool execution.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `tool_use_id: string`

      The id of the `agent.tool_use` event this result corresponds to.

    - `type: "agent.tool_result"`

      - `"agent.tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

  - `beta_managed_agents_agent_thread_message_received_event: object { id, content, from_session_thread_id, 3 more }`

    Delivery event written to the target thread's input stream when an agent-to-agent message arrives.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

      Message content blocks.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

    - `from_session_thread_id: string`

      Public `sthr_` ID of the thread that sent the message.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.thread_message_received"`

      - `"agent.thread_message_received"`

    - `from_agent_name: optional string`

      Name of the callable agent this message came from. Absent when received from the primary agent.

  - `beta_managed_agents_agent_thread_message_sent_event: object { id, content, processed_at, 3 more }`

    Observability event emitted to the sender's output stream when an agent-to-agent message is sent.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

      Message content blocks.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `to_session_thread_id: string`

      Public `sthr_` ID of the thread the message was sent to.

    - `type: "agent.thread_message_sent"`

      - `"agent.thread_message_sent"`

    - `to_agent_name: optional string`

      Name of the callable agent this message was sent to. Absent when sent to the primary agent.

  - `beta_managed_agents_agent_thread_context_compacted_event: object { id, processed_at, type }`

    Indicates that context compaction (summarization) occurred during the session.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.thread_context_compacted"`

      - `"agent.thread_context_compacted"`

  - `beta_managed_agents_session_error_event: object { id, error, processed_at, type }`

    An error event indicating a problem occurred during session execution.

    - `id: string`

      Unique identifier for this event.

    - `error: BetaManagedAgentsUnknownError or BetaManagedAgentsModelOverloadedError or BetaManagedAgentsModelRateLimitedError or 5 more`

      An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

      - `beta_managed_agents_unknown_error: object { message, retry_status, type }`

        An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `type: "retrying"`

              - `"retrying"`

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `type: "exhausted"`

              - `"exhausted"`

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

            - `type: "terminal"`

              - `"terminal"`

        - `type: "unknown_error"`

          - `"unknown_error"`

      - `beta_managed_agents_model_overloaded_error: object { message, retry_status, type }`

        The model is currently overloaded. Emitted after automatic retries are exhausted.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "model_overloaded_error"`

          - `"model_overloaded_error"`

      - `beta_managed_agents_model_rate_limited_error: object { message, retry_status, type }`

        The model request was rate-limited.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "model_rate_limited_error"`

          - `"model_rate_limited_error"`

      - `beta_managed_agents_model_request_failed_error: object { message, retry_status, type }`

        A model request failed for a reason other than overload or rate-limiting.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "model_request_failed_error"`

          - `"model_request_failed_error"`

      - `beta_managed_agents_mcp_connection_failed_error: object { mcp_server_name, message, retry_status, type }`

        Failed to connect to an MCP server.

        - `mcp_server_name: string`

          Name of the MCP server that failed to connect.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "mcp_connection_failed_error"`

          - `"mcp_connection_failed_error"`

      - `beta_managed_agents_mcp_authentication_failed_error: object { mcp_server_name, message, retry_status, type }`

        Authentication to an MCP server failed.

        - `mcp_server_name: string`

          Name of the MCP server that failed authentication.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "mcp_authentication_failed_error"`

          - `"mcp_authentication_failed_error"`

      - `beta_managed_agents_billing_error: object { message, retry_status, type }`

        The caller's organization or workspace cannot make model requests — out of credits or spend limit reached. Retrying with the same credentials will not succeed; the caller must resolve the billing state.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "billing_error"`

          - `"billing_error"`

      - `beta_managed_agents_credential_host_unreachable_error: object { credential_id, message, retry_status, 2 more }`

        An `environment_variable` credential's `auth.networking.allowed_hosts` includes a host the environment's network policy does not permit.

        - `credential_id: string`

          ID of the affected credential.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "credential_host_unreachable_error"`

          - `"credential_host_unreachable_error"`

        - `vault_id: string`

          ID of the vault containing the affected credential.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.error"`

      - `"session.error"`

  - `beta_managed_agents_session_status_rescheduled_event: object { id, processed_at, type }`

    Indicates the session is recovering from an error state and is rescheduled for execution.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.status_rescheduled"`

      - `"session.status_rescheduled"`

  - `beta_managed_agents_session_status_running_event: object { id, processed_at, type }`

    Indicates the session is actively running and the agent is working.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.status_running"`

      - `"session.status_running"`

  - `beta_managed_agents_session_status_idle_event: object { id, processed_at, stop_reason, type }`

    Indicates the agent has paused and is awaiting user input.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `stop_reason: BetaManagedAgentsSessionEndTurn or BetaManagedAgentsSessionRequiresAction or BetaManagedAgentsSessionRetriesExhausted`

      The agent completed its turn naturally and is ready for the next user message.

      - `beta_managed_agents_session_end_turn: object { type }`

        The agent completed its turn naturally and is ready for the next user message.

        - `type: "end_turn"`

          - `"end_turn"`

      - `beta_managed_agents_session_requires_action: object { event_ids, type }`

        The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

        - `event_ids: array of string`

          The ids of events the agent is blocked on. Resolving fewer than all re-emits `session.status_idle` with the remainder.

        - `type: "requires_action"`

          - `"requires_action"`

      - `beta_managed_agents_session_retries_exhausted: object { type }`

        The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

        - `type: "retries_exhausted"`

          - `"retries_exhausted"`

    - `type: "session.status_idle"`

      - `"session.status_idle"`

  - `beta_managed_agents_session_status_terminated_event: object { id, processed_at, type }`

    Indicates the session has terminated, either due to an error or completion.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.status_terminated"`

      - `"session.status_terminated"`

  - `beta_managed_agents_session_thread_created_event: object { id, agent_name, processed_at, 2 more }`

    Emitted when a subagent is spawned as a new thread. Written to the parent thread's output stream so clients observing the session see child creation.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the callable agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public `sthr_` ID of the newly created thread.

    - `type: "session.thread_created"`

      - `"session.thread_created"`

  - `beta_managed_agents_span_outcome_evaluation_start_event: object { id, iteration, outcome_id, 2 more }`

    Emitted when an outcome evaluation cycle begins.

    - `id: string`

      Unique identifier for this event.

    - `iteration: number`

      0-indexed revision cycle. 0 is the first evaluation; 1 is the re-evaluation after the first revision; etc.

    - `outcome_id: string`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.outcome_evaluation_start"`

      - `"span.outcome_evaluation_start"`

  - `beta_managed_agents_span_outcome_evaluation_end_event: object { id, explanation, iteration, 6 more }`

    Emitted when an outcome evaluation cycle completes. Carries the verdict and aggregate token usage. A verdict of `needs_revision` means another evaluation cycle follows; `satisfied`, `max_iterations_reached`, `failed`, or `interrupted` are terminal — no further evaluation cycles follow.

    - `id: string`

      Unique identifier for this event.

    - `explanation: string`

      Human-readable explanation of the verdict. For `needs_revision`, describes which criteria failed and why.

    - `iteration: number`

      0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

    - `outcome_evaluation_start_id: string`

      The id of the corresponding `span.outcome_evaluation_start` event.

    - `outcome_id: string`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `result: string`

      Evaluation verdict. 'satisfied': criteria met, session goes idle. 'needs_revision': criteria not met, another revision cycle follows. 'max_iterations_reached': evaluation budget exhausted with criteria still unmet — one final acknowledgment turn follows before the session goes idle, but no further evaluation runs. 'failed': grader determined the rubric does not apply to the deliverables. 'interrupted': user sent an interrupt while evaluation was in progress.

    - `type: "span.outcome_evaluation_end"`

      - `"span.outcome_evaluation_end"`

    - `usage: object { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }`

      Token usage for a single model request.

      - `cache_creation_input_tokens: number`

        Tokens used to create prompt cache in this request.

      - `cache_read_input_tokens: number`

        Tokens read from prompt cache in this request.

      - `input_tokens: number`

        Input tokens consumed by this request.

      - `output_tokens: number`

        Output tokens generated by this request.

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `"standard"`

        - `"fast"`

  - `beta_managed_agents_span_model_request_start_event: object { id, processed_at, type }`

    Emitted when a model request is initiated by the agent.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.model_request_start"`

      - `"span.model_request_start"`

  - `beta_managed_agents_span_model_request_end_event: object { id, is_error, model_request_start_id, 3 more }`

    Emitted when a model request completes.

    - `id: string`

      Unique identifier for this event.

    - `is_error: boolean`

      Whether the model request resulted in an error.

    - `model_request_start_id: string`

      The id of the corresponding `span.model_request_start` event.

    - `model_usage: object { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }`

      Token usage for a single model request.

      - `cache_creation_input_tokens: number`

        Tokens used to create prompt cache in this request.

      - `cache_read_input_tokens: number`

        Tokens read from prompt cache in this request.

      - `input_tokens: number`

        Input tokens consumed by this request.

      - `output_tokens: number`

        Output tokens generated by this request.

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.model_request_end"`

      - `"span.model_request_end"`

  - `beta_managed_agents_span_outcome_evaluation_ongoing_event: object { id, iteration, outcome_id, 2 more }`

    Periodic heartbeat emitted while an outcome evaluation cycle is in progress. Distinguishes 'evaluation is actively running' from 'evaluation is stuck' between the corresponding `span.outcome_evaluation_start` and `span.outcome_evaluation_end` events.

    - `id: string`

      Unique identifier for this event.

    - `iteration: number`

      0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

    - `outcome_id: string`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.outcome_evaluation_ongoing"`

      - `"span.outcome_evaluation_ongoing"`

  - `beta_managed_agents_user_define_outcome_event: object { id, description, max_iterations, 4 more }`

    Echo of a `user.define_outcome` input event. Carries the server-generated `outcome_id` that subsequent `span.outcome_evaluation_*` events reference.

    - `id: string`

      Unique identifier for this event.

    - `description: string`

      What the agent should produce. Copied from the input event.

    - `max_iterations: number`

      Evaluate-then-revise cycles before giving up. Default 3, max 20.

    - `outcome_id: string`

      Server-generated `outc_` ID for this outcome. Referenced by `span.outcome_evaluation_*` events and the session's `outcome_evaluations` list.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `rubric: BetaManagedAgentsFileRubric or BetaManagedAgentsTextRubric`

      Rubric for grading the quality of an outcome.

      - `beta_managed_agents_file_rubric: object { file_id, type }`

        Rubric referenced by a file uploaded via the Files API.

        - `file_id: string`

          ID of the rubric file.

        - `type: "file"`

          - `"file"`

      - `beta_managed_agents_text_rubric: object { content, type }`

        Rubric content provided inline as text.

        - `content: string`

          Rubric content. Plain text or markdown — the grader treats it as freeform text.

        - `type: "text"`

          - `"text"`

    - `type: "user.define_outcome"`

      - `"user.define_outcome"`

  - `beta_managed_agents_session_deleted_event: object { id, processed_at, type }`

    Emitted when a session has been deleted. Terminates any active event stream — no further events will be emitted for this session.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.deleted"`

      - `"session.deleted"`

  - `beta_managed_agents_session_thread_status_running_event: object { id, agent_name, processed_at, 2 more }`

    A session thread has begun executing. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that started running.

    - `type: "session.thread_status_running"`

      - `"session.thread_status_running"`

  - `beta_managed_agents_session_thread_status_idle_event: object { id, agent_name, processed_at, 3 more }`

    A session thread has yielded and is awaiting input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that went idle.

    - `stop_reason: BetaManagedAgentsSessionEndTurn or BetaManagedAgentsSessionRequiresAction or BetaManagedAgentsSessionRetriesExhausted`

      The agent completed its turn naturally and is ready for the next user message.

      - `beta_managed_agents_session_end_turn: object { type }`

        The agent completed its turn naturally and is ready for the next user message.

      - `beta_managed_agents_session_requires_action: object { event_ids, type }`

        The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

      - `beta_managed_agents_session_retries_exhausted: object { type }`

        The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

    - `type: "session.thread_status_idle"`

      - `"session.thread_status_idle"`

  - `beta_managed_agents_session_thread_status_terminated_event: object { id, agent_name, processed_at, 2 more }`

    A session thread has terminated and will accept no further input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that terminated.

    - `type: "session.thread_status_terminated"`

      - `"session.thread_status_terminated"`

  - `beta_managed_agents_user_tool_result_event: object { id, tool_use_id, type, 4 more }`

    Event sent by the client providing the result of an agent-toolset tool execution. Only valid on `self_hosted` environments, where sandbox-routed tools are executed by the client rather than the server.

    - `id: string`

      Unique identifier for this event.

    - `tool_use_id: string`

      The id of the `agent.tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: "user.tool_result"`

      - `"user.tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      Routes this result to a subagent thread. Copy from the `agent.tool_use` event's `session_thread_id`.

  - `beta_managed_agents_session_thread_status_rescheduled_event: object { id, agent_name, processed_at, 2 more }`

    A session thread hit a transient error and is retrying automatically. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that is retrying.

    - `type: "session.thread_status_rescheduled"`

      - `"session.thread_status_rescheduled"`

  - `beta_managed_agents_session_updated_event: object { id, processed_at, type, 3 more }`

    Emitted when an UpdateSession request changed at least one field. Carries only the fields that changed; absent fields were not part of the update. The new configuration applies from the next turn.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.updated"`

      - `"session.updated"`

    - `agent: optional object { id, description, mcp_servers, 8 more }`

      Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time.

      - `id: string`

      - `description: string`

      - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

        - `name: string`

        - `type: "url"`

          - `"url"`

        - `url: string`

      - `model: object { id, speed }`

        Model identifier and configuration.

        - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

          The model that will power your agent.

          See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

          - `"claude-fable-5"`

            Next generation of intelligence for the hardest knowledge work and coding problems

          - `"claude-opus-4-8"`

            Frontier intelligence for long-running agents and coding

          - `"claude-opus-4-7"`

            Frontier intelligence for long-running agents and coding

          - `"claude-opus-4-6"`

            Most intelligent model for building agents and coding

          - `"claude-sonnet-4-6"`

            Best combination of speed and intelligence

          - `"claude-haiku-4-5"`

            Fastest model with near-frontier intelligence

          - `"claude-haiku-4-5-20251001"`

            Fastest model with near-frontier intelligence

          - `"claude-opus-4-5"`

            Premium model combining maximum intelligence with practical performance

          - `"claude-opus-4-5-20251101"`

            Premium model combining maximum intelligence with practical performance

          - `"claude-sonnet-4-5"`

            High-performance model for agents and coding

          - `"claude-sonnet-4-5-20250929"`

            High-performance model for agents and coding

        - `speed: optional "standard" or "fast"`

          Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

          - `"standard"`

          - `"fast"`

      - `multiagent: object { agents, type }`

        Resolved coordinator topology with full agent definitions for each roster member.

        - `agents: array of BetaManagedAgentsSessionThreadAgent`

          Full `agent` definitions the coordinator may spawn as session threads.

          - `id: string`

          - `description: string`

          - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

            - `name: string`

            - `type: "url"`

            - `url: string`

          - `model: object { id, speed }`

            Model identifier and configuration.

            - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

              The model that will power your agent.

              See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

            - `speed: optional "standard" or "fast"`

              Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

          - `name: string`

          - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

            - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

              A resolved Anthropic-managed skill.

              - `skill_id: string`

              - `type: "anthropic"`

                - `"anthropic"`

              - `version: string`

            - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

              A resolved user-created custom skill.

              - `skill_id: string`

              - `type: "custom"`

                - `"custom"`

              - `version: string`

          - `system: string`

          - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

            - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

              - `configs: array of BetaManagedAgentsAgentToolConfig`

                - `enabled: boolean`

                - `name: "bash" or "edit" or "read" or 5 more`

                  Built-in agent tool identifier.

                  - `"bash"`

                  - `"edit"`

                  - `"read"`

                  - `"write"`

                  - `"glob"`

                  - `"grep"`

                  - `"web_fetch"`

                  - `"web_search"`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                    - `type: "always_allow"`

                      - `"always_allow"`

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

                    - `type: "always_ask"`

                      - `"always_ask"`

              - `default_config: object { enabled, permission_policy }`

                Resolved default configuration for agent tools.

                - `enabled: boolean`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

              - `type: "agent_toolset_20260401"`

                - `"agent_toolset_20260401"`

            - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

              - `configs: array of BetaManagedAgentsMCPToolConfig`

                - `enabled: boolean`

                - `name: string`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

              - `default_config: object { enabled, permission_policy }`

                Resolved default configuration for all tools from an MCP server.

                - `enabled: boolean`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

              - `mcp_server_name: string`

              - `type: "mcp_toolset"`

                - `"mcp_toolset"`

            - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

              A custom tool as returned in API responses.

              - `description: string`

              - `input_schema: object { type, properties, required }`

                JSON Schema for custom tool input parameters.

                - `type: "object"`

                - `properties: optional map[unknown]`

                - `required: optional array of string`

              - `name: string`

              - `type: "custom"`

                - `"custom"`

          - `type: "agent"`

            - `"agent"`

          - `version: number`

        - `type: "coordinator"`

          - `"coordinator"`

      - `name: string`

      - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

        - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

          A resolved Anthropic-managed skill.

        - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

          A resolved user-created custom skill.

      - `system: string`

      - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

        - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

        - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

        - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

          A custom tool as returned in API responses.

      - `type: "agent"`

        - `"agent"`

      - `version: number`

    - `metadata: optional map[string]`

      The session's full metadata bag after the update. Present when the update set non-empty metadata; absent when metadata was unchanged or cleared to empty.

    - `title: optional string`

      The session's new title. Present only when the update changed it.

  - `beta_managed_agents_system_message_event: object { id, content, type, processed_at }`

    A mid-conversation system message event. Carries system-role content that is appended to the session as a `role: "system"` turn.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsSystemContentBlock`

      System content blocks. Text-only.

      - `text: string`

        The text content.

      - `type: "text"`

        - `"text"`

    - `type: "system.message"`

      - `"system.message"`

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

### Example

```cli
ant beta:sessions:events stream \
  --api-key my-anthropic-api-key \
  --session-id sesn_011CZkZAtmR3yMPDzynEDxu7
```

#### Response

```json
{
  "id": "sevt_011CZkZGOp0iBcp4kaQSihUmy",
  "content": [
    {
      "text": "Where is my order #1234?",
      "type": "text"
    }
  ],
  "type": "user.message",
  "processed_at": "2026-03-15T10:00:00Z"
}
```

## Domain Types

### Beta Managed Agents Agent Custom Tool Use Event

- `beta_managed_agents_agent_custom_tool_use_event: object { id, input, name, 3 more }`

  Event emitted when the agent calls a custom tool. The session goes idle until the client sends a `user.custom_tool_result` event with the result.

  - `id: string`

    Unique identifier for this event.

  - `input: map[unknown]`

    Input parameters for the tool call.

  - `name: string`

    Name of the custom tool being called.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `type: "agent.custom_tool_use"`

    - `"agent.custom_tool_use"`

  - `session_thread_id: optional string`

    When set, this event was cross-posted from a subagent's thread to surface its custom tool use on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.custom_tool_result` event to route the result back.

### Beta Managed Agents Agent MCP Tool Result Event

- `beta_managed_agents_agent_mcp_tool_result_event: object { id, mcp_tool_use_id, processed_at, 3 more }`

  Event representing the result of an MCP tool execution.

  - `id: string`

    Unique identifier for this event.

  - `mcp_tool_use_id: string`

    The id of the `agent.mcp_tool_use` event this result corresponds to.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `type: "agent.mcp_tool_result"`

    - `"agent.mcp_tool_result"`

  - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

    The result content returned by the tool.

    - `beta_managed_agents_text_block: object { text, type }`

      Regular text content.

      - `text: string`

        The text content.

      - `type: "text"`

        - `"text"`

    - `beta_managed_agents_image_block: object { source, type }`

      Image content specified directly as base64 data or as a reference via a URL.

      - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

        Union type for image source variants.

        - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

          Base64-encoded image data.

          - `data: string`

            Base64-encoded image data.

          - `media_type: string`

            MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_url_image_source: object { type, url }`

          Image referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the image to fetch.

        - `beta_managed_agents_file_image_source: object { file_id, type }`

          Image referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "image"`

        - `"image"`

    - `beta_managed_agents_document_block: object { source, type, context, title }`

      Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

        Union type for document source variants.

        - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

          Base64-encoded document data.

          - `data: string`

            Base64-encoded document data.

          - `media_type: string`

            MIME type of the document (e.g., "application/pdf").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

          Plain text document content.

          - `data: string`

            The plain text content.

          - `media_type: "text/plain"`

            MIME type of the text content. Must be "text/plain".

            - `"text/plain"`

          - `type: "text"`

            - `"text"`

        - `beta_managed_agents_url_document_source: object { type, url }`

          Document referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the document to fetch.

        - `beta_managed_agents_file_document_source: object { file_id, type }`

          Document referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "document"`

        - `"document"`

      - `context: optional string`

        Additional context about the document for the model.

      - `title: optional string`

        The title of the document.

    - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

      A block containing a web search result.

      - `citations: object { enabled }`

        Citation settings for a search result.

        - `enabled: boolean`

          Whether citations are enabled for this search result.

      - `content: array of BetaManagedAgentsSearchResultContent`

        Array of text content blocks from the search result.

        - `text: string`

          The text content.

        - `type: "text"`

          - `"text"`

      - `source: string`

        The URL source of the search result.

      - `title: string`

        The title of the search result.

      - `type: "search_result"`

        - `"search_result"`

  - `is_error: optional boolean`

    Whether the tool execution resulted in an error.

### Beta Managed Agents Agent MCP Tool Use Event

- `beta_managed_agents_agent_mcp_tool_use_event: object { id, input, mcp_server_name, 5 more }`

  Event emitted when the agent invokes a tool provided by an MCP server.

  - `id: string`

    Unique identifier for this event.

  - `input: map[unknown]`

    Input parameters for the tool call.

  - `mcp_server_name: string`

    Name of the MCP server providing the tool.

  - `name: string`

    Name of the MCP tool being used.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `type: "agent.mcp_tool_use"`

    - `"agent.mcp_tool_use"`

  - `evaluated_permission: optional "allow" or "ask" or "deny"`

    AgentEvaluatedPermission enum

    - `"allow"`

    - `"ask"`

    - `"deny"`

  - `session_thread_id: optional string`

    When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

### Beta Managed Agents Agent Message Event

- `beta_managed_agents_agent_message_event: object { id, content, processed_at, type }`

  An agent response event in the session conversation.

  - `id: string`

    Unique identifier for this event.

  - `content: array of BetaManagedAgentsTextBlock`

    Array of text blocks comprising the agent response.

    - `text: string`

      The text content.

    - `type: "text"`

      - `"text"`

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `type: "agent.message"`

    - `"agent.message"`

### Beta Managed Agents Agent Thinking Event

- `beta_managed_agents_agent_thinking_event: object { id, processed_at, type }`

  Indicates the agent is making forward progress via extended thinking. A progress signal, not a content carrier.

  - `id: string`

    Unique identifier for this event.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `type: "agent.thinking"`

    - `"agent.thinking"`

### Beta Managed Agents Agent Thread Context Compacted Event

- `beta_managed_agents_agent_thread_context_compacted_event: object { id, processed_at, type }`

  Indicates that context compaction (summarization) occurred during the session.

  - `id: string`

    Unique identifier for this event.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `type: "agent.thread_context_compacted"`

    - `"agent.thread_context_compacted"`

### Beta Managed Agents Agent Thread Message Received Event

- `beta_managed_agents_agent_thread_message_received_event: object { id, content, from_session_thread_id, 3 more }`

  Delivery event written to the target thread's input stream when an agent-to-agent message arrives.

  - `id: string`

    Unique identifier for this event.

  - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

    Message content blocks.

    - `beta_managed_agents_text_block: object { text, type }`

      Regular text content.

      - `text: string`

        The text content.

      - `type: "text"`

        - `"text"`

    - `beta_managed_agents_image_block: object { source, type }`

      Image content specified directly as base64 data or as a reference via a URL.

      - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

        Union type for image source variants.

        - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

          Base64-encoded image data.

          - `data: string`

            Base64-encoded image data.

          - `media_type: string`

            MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_url_image_source: object { type, url }`

          Image referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the image to fetch.

        - `beta_managed_agents_file_image_source: object { file_id, type }`

          Image referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "image"`

        - `"image"`

    - `beta_managed_agents_document_block: object { source, type, context, title }`

      Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

        Union type for document source variants.

        - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

          Base64-encoded document data.

          - `data: string`

            Base64-encoded document data.

          - `media_type: string`

            MIME type of the document (e.g., "application/pdf").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

          Plain text document content.

          - `data: string`

            The plain text content.

          - `media_type: "text/plain"`

            MIME type of the text content. Must be "text/plain".

            - `"text/plain"`

          - `type: "text"`

            - `"text"`

        - `beta_managed_agents_url_document_source: object { type, url }`

          Document referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the document to fetch.

        - `beta_managed_agents_file_document_source: object { file_id, type }`

          Document referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "document"`

        - `"document"`

      - `context: optional string`

        Additional context about the document for the model.

      - `title: optional string`

        The title of the document.

  - `from_session_thread_id: string`

    Public `sthr_` ID of the thread that sent the message.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `type: "agent.thread_message_received"`

    - `"agent.thread_message_received"`

  - `from_agent_name: optional string`

    Name of the callable agent this message came from. Absent when received from the primary agent.

### Beta Managed Agents Agent Thread Message Sent Event

- `beta_managed_agents_agent_thread_message_sent_event: object { id, content, processed_at, 3 more }`

  Observability event emitted to the sender's output stream when an agent-to-agent message is sent.

  - `id: string`

    Unique identifier for this event.

  - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

    Message content blocks.

    - `beta_managed_agents_text_block: object { text, type }`

      Regular text content.

      - `text: string`

        The text content.

      - `type: "text"`

        - `"text"`

    - `beta_managed_agents_image_block: object { source, type }`

      Image content specified directly as base64 data or as a reference via a URL.

      - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

        Union type for image source variants.

        - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

          Base64-encoded image data.

          - `data: string`

            Base64-encoded image data.

          - `media_type: string`

            MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_url_image_source: object { type, url }`

          Image referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the image to fetch.

        - `beta_managed_agents_file_image_source: object { file_id, type }`

          Image referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "image"`

        - `"image"`

    - `beta_managed_agents_document_block: object { source, type, context, title }`

      Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

        Union type for document source variants.

        - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

          Base64-encoded document data.

          - `data: string`

            Base64-encoded document data.

          - `media_type: string`

            MIME type of the document (e.g., "application/pdf").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

          Plain text document content.

          - `data: string`

            The plain text content.

          - `media_type: "text/plain"`

            MIME type of the text content. Must be "text/plain".

            - `"text/plain"`

          - `type: "text"`

            - `"text"`

        - `beta_managed_agents_url_document_source: object { type, url }`

          Document referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the document to fetch.

        - `beta_managed_agents_file_document_source: object { file_id, type }`

          Document referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "document"`

        - `"document"`

      - `context: optional string`

        Additional context about the document for the model.

      - `title: optional string`

        The title of the document.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `to_session_thread_id: string`

    Public `sthr_` ID of the thread the message was sent to.

  - `type: "agent.thread_message_sent"`

    - `"agent.thread_message_sent"`

  - `to_agent_name: optional string`

    Name of the callable agent this message was sent to. Absent when sent to the primary agent.

### Beta Managed Agents Agent Tool Result Event

- `beta_managed_agents_agent_tool_result_event: object { id, processed_at, tool_use_id, 3 more }`

  Event representing the result of an agent tool execution.

  - `id: string`

    Unique identifier for this event.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `tool_use_id: string`

    The id of the `agent.tool_use` event this result corresponds to.

  - `type: "agent.tool_result"`

    - `"agent.tool_result"`

  - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

    The result content returned by the tool.

    - `beta_managed_agents_text_block: object { text, type }`

      Regular text content.

      - `text: string`

        The text content.

      - `type: "text"`

        - `"text"`

    - `beta_managed_agents_image_block: object { source, type }`

      Image content specified directly as base64 data or as a reference via a URL.

      - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

        Union type for image source variants.

        - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

          Base64-encoded image data.

          - `data: string`

            Base64-encoded image data.

          - `media_type: string`

            MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_url_image_source: object { type, url }`

          Image referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the image to fetch.

        - `beta_managed_agents_file_image_source: object { file_id, type }`

          Image referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "image"`

        - `"image"`

    - `beta_managed_agents_document_block: object { source, type, context, title }`

      Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

        Union type for document source variants.

        - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

          Base64-encoded document data.

          - `data: string`

            Base64-encoded document data.

          - `media_type: string`

            MIME type of the document (e.g., "application/pdf").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

          Plain text document content.

          - `data: string`

            The plain text content.

          - `media_type: "text/plain"`

            MIME type of the text content. Must be "text/plain".

            - `"text/plain"`

          - `type: "text"`

            - `"text"`

        - `beta_managed_agents_url_document_source: object { type, url }`

          Document referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the document to fetch.

        - `beta_managed_agents_file_document_source: object { file_id, type }`

          Document referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "document"`

        - `"document"`

      - `context: optional string`

        Additional context about the document for the model.

      - `title: optional string`

        The title of the document.

    - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

      A block containing a web search result.

      - `citations: object { enabled }`

        Citation settings for a search result.

        - `enabled: boolean`

          Whether citations are enabled for this search result.

      - `content: array of BetaManagedAgentsSearchResultContent`

        Array of text content blocks from the search result.

        - `text: string`

          The text content.

        - `type: "text"`

          - `"text"`

      - `source: string`

        The URL source of the search result.

      - `title: string`

        The title of the search result.

      - `type: "search_result"`

        - `"search_result"`

  - `is_error: optional boolean`

    Whether the tool execution resulted in an error.

### Beta Managed Agents Agent Tool Use Event

- `beta_managed_agents_agent_tool_use_event: object { id, input, name, 4 more }`

  Event emitted when the agent invokes a built-in agent tool.

  - `id: string`

    Unique identifier for this event.

  - `input: map[unknown]`

    Input parameters for the tool call.

  - `name: string`

    Name of the agent tool being used.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `type: "agent.tool_use"`

    - `"agent.tool_use"`

  - `evaluated_permission: optional "allow" or "ask" or "deny"`

    AgentEvaluatedPermission enum

    - `"allow"`

    - `"ask"`

    - `"deny"`

  - `session_thread_id: optional string`

    When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

### Beta Managed Agents Base64 Document Source

- `beta_managed_agents_base64_document_source: object { data, media_type, type }`

  Base64-encoded document data.

  - `data: string`

    Base64-encoded document data.

  - `media_type: string`

    MIME type of the document (e.g., "application/pdf").

  - `type: "base64"`

    - `"base64"`

### Beta Managed Agents Base64 Image Source

- `beta_managed_agents_base64_image_source: object { data, media_type, type }`

  Base64-encoded image data.

  - `data: string`

    Base64-encoded image data.

  - `media_type: string`

    MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

  - `type: "base64"`

    - `"base64"`

### Beta Managed Agents Billing Error

- `beta_managed_agents_billing_error: object { message, retry_status, type }`

  The caller's organization or workspace cannot make model requests — out of credits or spend limit reached. Retrying with the same credentials will not succeed; the caller must resolve the billing state.

  - `message: string`

    Human-readable error description.

  - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

    What the client should do next in response to this error.

    - `beta_managed_agents_retry_status_retrying: object { type }`

      The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

      - `type: "retrying"`

        - `"retrying"`

    - `beta_managed_agents_retry_status_exhausted: object { type }`

      This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

      - `type: "exhausted"`

        - `"exhausted"`

    - `beta_managed_agents_retry_status_terminal: object { type }`

      The session encountered a terminal error and will transition to `terminated` state.

      - `type: "terminal"`

        - `"terminal"`

  - `type: "billing_error"`

    - `"billing_error"`

### Beta Managed Agents Credential Host Unreachable Error

- `beta_managed_agents_credential_host_unreachable_error: object { credential_id, message, retry_status, 2 more }`

  An `environment_variable` credential's `auth.networking.allowed_hosts` includes a host the environment's network policy does not permit.

  - `credential_id: string`

    ID of the affected credential.

  - `message: string`

    Human-readable error description.

  - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

    What the client should do next in response to this error.

    - `beta_managed_agents_retry_status_retrying: object { type }`

      The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

      - `type: "retrying"`

        - `"retrying"`

    - `beta_managed_agents_retry_status_exhausted: object { type }`

      This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

      - `type: "exhausted"`

        - `"exhausted"`

    - `beta_managed_agents_retry_status_terminal: object { type }`

      The session encountered a terminal error and will transition to `terminated` state.

      - `type: "terminal"`

        - `"terminal"`

  - `type: "credential_host_unreachable_error"`

    - `"credential_host_unreachable_error"`

  - `vault_id: string`

    ID of the vault containing the affected credential.

### Beta Managed Agents Document Block

- `beta_managed_agents_document_block: object { source, type, context, title }`

  Document content, either specified directly as base64 data, as text, or as a reference via a URL.

  - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

    Union type for document source variants.

    - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

      Base64-encoded document data.

      - `data: string`

        Base64-encoded document data.

      - `media_type: string`

        MIME type of the document (e.g., "application/pdf").

      - `type: "base64"`

        - `"base64"`

    - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

      Plain text document content.

      - `data: string`

        The plain text content.

      - `media_type: "text/plain"`

        MIME type of the text content. Must be "text/plain".

        - `"text/plain"`

      - `type: "text"`

        - `"text"`

    - `beta_managed_agents_url_document_source: object { type, url }`

      Document referenced by URL.

      - `type: "url"`

        - `"url"`

      - `url: string`

        URL of the document to fetch.

    - `beta_managed_agents_file_document_source: object { file_id, type }`

      Document referenced by file ID.

      - `file_id: string`

        ID of a previously uploaded file.

      - `type: "file"`

        - `"file"`

  - `type: "document"`

    - `"document"`

  - `context: optional string`

    Additional context about the document for the model.

  - `title: optional string`

    The title of the document.

### Beta Managed Agents Event Params

- `beta_managed_agents_event_params: BetaManagedAgentsUserMessageEventParams or BetaManagedAgentsUserInterruptEventParams or BetaManagedAgentsUserToolConfirmationEventParams or 4 more`

  Union type for event parameters that can be sent to a session.

  - `beta_managed_agents_user_message_event_params: object { content, type }`

    Parameters for sending a user message to the session.

    - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

      Array of content blocks for the user message.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

        - `text: string`

          The text content.

        - `type: "text"`

          - `"text"`

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

        - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

          Union type for image source variants.

          - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

            Base64-encoded image data.

            - `data: string`

              Base64-encoded image data.

            - `media_type: string`

              MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

            - `type: "base64"`

              - `"base64"`

          - `beta_managed_agents_url_image_source: object { type, url }`

            Image referenced by URL.

            - `type: "url"`

              - `"url"`

            - `url: string`

              URL of the image to fetch.

          - `beta_managed_agents_file_image_source: object { file_id, type }`

            Image referenced by file ID.

            - `file_id: string`

              ID of a previously uploaded file.

            - `type: "file"`

              - `"file"`

        - `type: "image"`

          - `"image"`

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

          Union type for document source variants.

          - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

            Base64-encoded document data.

            - `data: string`

              Base64-encoded document data.

            - `media_type: string`

              MIME type of the document (e.g., "application/pdf").

            - `type: "base64"`

              - `"base64"`

          - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

            Plain text document content.

            - `data: string`

              The plain text content.

            - `media_type: "text/plain"`

              MIME type of the text content. Must be "text/plain".

              - `"text/plain"`

            - `type: "text"`

              - `"text"`

          - `beta_managed_agents_url_document_source: object { type, url }`

            Document referenced by URL.

            - `type: "url"`

              - `"url"`

            - `url: string`

              URL of the document to fetch.

          - `beta_managed_agents_file_document_source: object { file_id, type }`

            Document referenced by file ID.

            - `file_id: string`

              ID of a previously uploaded file.

            - `type: "file"`

              - `"file"`

        - `type: "document"`

          - `"document"`

        - `context: optional string`

          Additional context about the document for the model.

        - `title: optional string`

          The title of the document.

    - `type: "user.message"`

      - `"user.message"`

  - `beta_managed_agents_user_interrupt_event_params: object { type, session_thread_id }`

    Parameters for sending an interrupt to pause the agent.

    - `type: "user.interrupt"`

      - `"user.interrupt"`

    - `session_thread_id: optional string`

      If absent, interrupts every non-archived thread in a multiagent session (or the primary alone in a single-agent session). If present, interrupts only the named thread.

  - `beta_managed_agents_user_tool_confirmation_event_params: object { result, tool_use_id, type, deny_message }`

    Parameters for confirming or denying a tool execution request.

    - `result: "allow" or "deny"`

      UserToolConfirmationResult enum

      - `"allow"`

      - `"deny"`

    - `tool_use_id: string`

      The id of the `agent.tool_use` or `agent.mcp_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: "user.tool_confirmation"`

      - `"user.tool_confirmation"`

    - `deny_message: optional string`

      Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'.

  - `beta_managed_agents_user_custom_tool_result_event_params: object { custom_tool_use_id, type, content, is_error }`

    Parameters for providing the result of a custom tool execution.

    - `custom_tool_use_id: string`

      The id of the `agent.custom_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: "user.custom_tool_result"`

      - `"user.custom_tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

        - `citations: object { enabled }`

          Citation settings for a search result.

          - `enabled: boolean`

            Whether citations are enabled for this search result.

        - `content: array of BetaManagedAgentsSearchResultContent`

          Array of text content blocks from the search result.

          - `text: string`

            The text content.

          - `type: "text"`

            - `"text"`

        - `source: string`

          The URL source of the search result.

        - `title: string`

          The title of the search result.

        - `type: "search_result"`

          - `"search_result"`

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

  - `beta_managed_agents_user_define_outcome_event_params: object { description, rubric, type, max_iterations }`

    Parameters for defining an outcome the agent should work toward. The agent begins work on receipt.

    - `description: string`

      What the agent should produce. This is the task specification.

    - `rubric: BetaManagedAgentsFileRubricParams or BetaManagedAgentsTextRubricParams`

      Rubric for grading the quality of an outcome.

      - `beta_managed_agents_file_rubric_params: object { file_id, type }`

        Rubric referenced by a file uploaded via the Files API.

        - `file_id: string`

          ID of the rubric file.

        - `type: "file"`

          - `"file"`

      - `beta_managed_agents_text_rubric_params: object { content, type }`

        Rubric content provided inline as text.

        - `content: string`

          Rubric content. Plain text or markdown — the grader treats it as freeform text. Maximum 262144 characters.

        - `type: "text"`

          - `"text"`

    - `type: "user.define_outcome"`

      - `"user.define_outcome"`

    - `max_iterations: optional number`

      Eval→revision cycles before giving up. Default 3, max 20.

  - `beta_managed_agents_user_tool_result_event_params: object { tool_use_id, type, content, is_error }`

    Parameters for providing the result of an agent-toolset tool execution. Only valid on `self_hosted` environments, where sandbox-routed tools are executed by the client rather than the server.

    - `tool_use_id: string`

      The id of the `agent.tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: "user.tool_result"`

      - `"user.tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

  - `beta_managed_agents_system_message_event_params: object { content, type }`

    Privileged context for the accompanying turn and all subsequent turns, appended to the session's system context as a `role: "system"` turn rather than replacing the top-level system prompt. At most one per request: it must be the final event and immediately follow the `user.message`, `user.tool_result`, or `user.custom_tool_result` it accompanies. Only supported on models that accept mid-conversation system messages.

    - `content: array of BetaManagedAgentsSystemContentBlock`

      System content blocks to append. Text-only.

      - `text: string`

        The text content.

      - `type: "text"`

        - `"text"`

    - `type: "system.message"`

      - `"system.message"`

### Beta Managed Agents File Document Source

- `beta_managed_agents_file_document_source: object { file_id, type }`

  Document referenced by file ID.

  - `file_id: string`

    ID of a previously uploaded file.

  - `type: "file"`

    - `"file"`

### Beta Managed Agents File Image Source

- `beta_managed_agents_file_image_source: object { file_id, type }`

  Image referenced by file ID.

  - `file_id: string`

    ID of a previously uploaded file.

  - `type: "file"`

    - `"file"`

### Beta Managed Agents File Rubric

- `beta_managed_agents_file_rubric: object { file_id, type }`

  Rubric referenced by a file uploaded via the Files API.

  - `file_id: string`

    ID of the rubric file.

  - `type: "file"`

    - `"file"`

### Beta Managed Agents File Rubric Params

- `beta_managed_agents_file_rubric_params: object { file_id, type }`

  Rubric referenced by a file uploaded via the Files API.

  - `file_id: string`

    ID of the rubric file.

  - `type: "file"`

    - `"file"`

### Beta Managed Agents Image Block

- `beta_managed_agents_image_block: object { source, type }`

  Image content specified directly as base64 data or as a reference via a URL.

  - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

    Union type for image source variants.

    - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

      Base64-encoded image data.

      - `data: string`

        Base64-encoded image data.

      - `media_type: string`

        MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

      - `type: "base64"`

        - `"base64"`

    - `beta_managed_agents_url_image_source: object { type, url }`

      Image referenced by URL.

      - `type: "url"`

        - `"url"`

      - `url: string`

        URL of the image to fetch.

    - `beta_managed_agents_file_image_source: object { file_id, type }`

      Image referenced by file ID.

      - `file_id: string`

        ID of a previously uploaded file.

      - `type: "file"`

        - `"file"`

  - `type: "image"`

    - `"image"`

### Beta Managed Agents MCP Authentication Failed Error

- `beta_managed_agents_mcp_authentication_failed_error: object { mcp_server_name, message, retry_status, type }`

  Authentication to an MCP server failed.

  - `mcp_server_name: string`

    Name of the MCP server that failed authentication.

  - `message: string`

    Human-readable error description.

  - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

    What the client should do next in response to this error.

    - `beta_managed_agents_retry_status_retrying: object { type }`

      The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

      - `type: "retrying"`

        - `"retrying"`

    - `beta_managed_agents_retry_status_exhausted: object { type }`

      This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

      - `type: "exhausted"`

        - `"exhausted"`

    - `beta_managed_agents_retry_status_terminal: object { type }`

      The session encountered a terminal error and will transition to `terminated` state.

      - `type: "terminal"`

        - `"terminal"`

  - `type: "mcp_authentication_failed_error"`

    - `"mcp_authentication_failed_error"`

### Beta Managed Agents MCP Connection Failed Error

- `beta_managed_agents_mcp_connection_failed_error: object { mcp_server_name, message, retry_status, type }`

  Failed to connect to an MCP server.

  - `mcp_server_name: string`

    Name of the MCP server that failed to connect.

  - `message: string`

    Human-readable error description.

  - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

    What the client should do next in response to this error.

    - `beta_managed_agents_retry_status_retrying: object { type }`

      The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

      - `type: "retrying"`

        - `"retrying"`

    - `beta_managed_agents_retry_status_exhausted: object { type }`

      This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

      - `type: "exhausted"`

        - `"exhausted"`

    - `beta_managed_agents_retry_status_terminal: object { type }`

      The session encountered a terminal error and will transition to `terminated` state.

      - `type: "terminal"`

        - `"terminal"`

  - `type: "mcp_connection_failed_error"`

    - `"mcp_connection_failed_error"`

### Beta Managed Agents Model Overloaded Error

- `beta_managed_agents_model_overloaded_error: object { message, retry_status, type }`

  The model is currently overloaded. Emitted after automatic retries are exhausted.

  - `message: string`

    Human-readable error description.

  - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

    What the client should do next in response to this error.

    - `beta_managed_agents_retry_status_retrying: object { type }`

      The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

      - `type: "retrying"`

        - `"retrying"`

    - `beta_managed_agents_retry_status_exhausted: object { type }`

      This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

      - `type: "exhausted"`

        - `"exhausted"`

    - `beta_managed_agents_retry_status_terminal: object { type }`

      The session encountered a terminal error and will transition to `terminated` state.

      - `type: "terminal"`

        - `"terminal"`

  - `type: "model_overloaded_error"`

    - `"model_overloaded_error"`

### Beta Managed Agents Model Rate Limited Error

- `beta_managed_agents_model_rate_limited_error: object { message, retry_status, type }`

  The model request was rate-limited.

  - `message: string`

    Human-readable error description.

  - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

    What the client should do next in response to this error.

    - `beta_managed_agents_retry_status_retrying: object { type }`

      The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

      - `type: "retrying"`

        - `"retrying"`

    - `beta_managed_agents_retry_status_exhausted: object { type }`

      This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

      - `type: "exhausted"`

        - `"exhausted"`

    - `beta_managed_agents_retry_status_terminal: object { type }`

      The session encountered a terminal error and will transition to `terminated` state.

      - `type: "terminal"`

        - `"terminal"`

  - `type: "model_rate_limited_error"`

    - `"model_rate_limited_error"`

### Beta Managed Agents Model Request Failed Error

- `beta_managed_agents_model_request_failed_error: object { message, retry_status, type }`

  A model request failed for a reason other than overload or rate-limiting.

  - `message: string`

    Human-readable error description.

  - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

    What the client should do next in response to this error.

    - `beta_managed_agents_retry_status_retrying: object { type }`

      The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

      - `type: "retrying"`

        - `"retrying"`

    - `beta_managed_agents_retry_status_exhausted: object { type }`

      This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

      - `type: "exhausted"`

        - `"exhausted"`

    - `beta_managed_agents_retry_status_terminal: object { type }`

      The session encountered a terminal error and will transition to `terminated` state.

      - `type: "terminal"`

        - `"terminal"`

  - `type: "model_request_failed_error"`

    - `"model_request_failed_error"`

### Beta Managed Agents Plain Text Document Source

- `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

  Plain text document content.

  - `data: string`

    The plain text content.

  - `media_type: "text/plain"`

    MIME type of the text content. Must be "text/plain".

    - `"text/plain"`

  - `type: "text"`

    - `"text"`

### Beta Managed Agents Retry Status Exhausted

- `beta_managed_agents_retry_status_exhausted: object { type }`

  This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

  - `type: "exhausted"`

    - `"exhausted"`

### Beta Managed Agents Retry Status Retrying

- `beta_managed_agents_retry_status_retrying: object { type }`

  The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

  - `type: "retrying"`

    - `"retrying"`

### Beta Managed Agents Retry Status Terminal

- `beta_managed_agents_retry_status_terminal: object { type }`

  The session encountered a terminal error and will transition to `terminated` state.

  - `type: "terminal"`

    - `"terminal"`

### Beta Managed Agents Search Result Block

- `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

  A block containing a web search result.

  - `citations: object { enabled }`

    Citation settings for a search result.

    - `enabled: boolean`

      Whether citations are enabled for this search result.

  - `content: array of BetaManagedAgentsSearchResultContent`

    Array of text content blocks from the search result.

    - `text: string`

      The text content.

    - `type: "text"`

      - `"text"`

  - `source: string`

    The URL source of the search result.

  - `title: string`

    The title of the search result.

  - `type: "search_result"`

    - `"search_result"`

### Beta Managed Agents Search Result Citations

- `beta_managed_agents_search_result_citations: object { enabled }`

  Citation settings for a search result.

  - `enabled: boolean`

    Whether citations are enabled for this search result.

### Beta Managed Agents Search Result Content

- `beta_managed_agents_search_result_content: object { text, type }`

  Text content within a search result.

  - `text: string`

    The text content.

  - `type: "text"`

    - `"text"`

### Beta Managed Agents Send Session Events

- `beta_managed_agents_send_session_events: object { data }`

  Events that were successfully sent to the session.

  - `data: optional array of BetaManagedAgentsUserMessageEvent or BetaManagedAgentsUserInterruptEvent or BetaManagedAgentsUserToolConfirmationEvent or 4 more`

    Sent events

    - `beta_managed_agents_user_message_event: object { id, content, type, processed_at }`

      A user message event in the session conversation.

      - `id: string`

        Unique identifier for this event.

      - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

        Array of content blocks comprising the user message.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

          - `text: string`

            The text content.

          - `type: "text"`

            - `"text"`

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

          - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

            Union type for image source variants.

            - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

              Base64-encoded image data.

              - `data: string`

                Base64-encoded image data.

              - `media_type: string`

                MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

              - `type: "base64"`

                - `"base64"`

            - `beta_managed_agents_url_image_source: object { type, url }`

              Image referenced by URL.

              - `type: "url"`

                - `"url"`

              - `url: string`

                URL of the image to fetch.

            - `beta_managed_agents_file_image_source: object { file_id, type }`

              Image referenced by file ID.

              - `file_id: string`

                ID of a previously uploaded file.

              - `type: "file"`

                - `"file"`

          - `type: "image"`

            - `"image"`

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

          - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

            Union type for document source variants.

            - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

              Base64-encoded document data.

              - `data: string`

                Base64-encoded document data.

              - `media_type: string`

                MIME type of the document (e.g., "application/pdf").

              - `type: "base64"`

                - `"base64"`

            - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

              Plain text document content.

              - `data: string`

                The plain text content.

              - `media_type: "text/plain"`

                MIME type of the text content. Must be "text/plain".

                - `"text/plain"`

              - `type: "text"`

                - `"text"`

            - `beta_managed_agents_url_document_source: object { type, url }`

              Document referenced by URL.

              - `type: "url"`

                - `"url"`

              - `url: string`

                URL of the document to fetch.

            - `beta_managed_agents_file_document_source: object { file_id, type }`

              Document referenced by file ID.

              - `file_id: string`

                ID of a previously uploaded file.

              - `type: "file"`

                - `"file"`

          - `type: "document"`

            - `"document"`

          - `context: optional string`

            Additional context about the document for the model.

          - `title: optional string`

            The title of the document.

      - `type: "user.message"`

        - `"user.message"`

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

    - `beta_managed_agents_user_interrupt_event: object { id, type, processed_at, session_thread_id }`

      An interrupt event that pauses agent execution and returns control to the user.

      - `id: string`

        Unique identifier for this event.

      - `type: "user.interrupt"`

        - `"user.interrupt"`

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

      - `session_thread_id: optional string`

        If absent, interrupts every non-archived thread in a multiagent session (or the primary alone in a single-agent session). If present, interrupts only the named thread.

    - `beta_managed_agents_user_tool_confirmation_event: object { id, result, tool_use_id, 4 more }`

      A tool confirmation event that approves or denies a pending tool execution.

      - `id: string`

        Unique identifier for this event.

      - `result: "allow" or "deny"`

        UserToolConfirmationResult enum

        - `"allow"`

        - `"deny"`

      - `tool_use_id: string`

        The id of the `agent.tool_use` or `agent.mcp_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

      - `type: "user.tool_confirmation"`

        - `"user.tool_confirmation"`

      - `deny_message: optional string`

        Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'.

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

      - `session_thread_id: optional string`

        When set, the confirmation routes to this subagent's thread rather than the primary. Echo this from the `session_thread_id` on the `agent.tool_use` or `agent.mcp_tool_use` event that prompted the approval.

    - `beta_managed_agents_user_custom_tool_result_event: object { id, custom_tool_use_id, type, 4 more }`

      Event sent by the client providing the result of a custom tool execution.

      - `id: string`

        Unique identifier for this event.

      - `custom_tool_use_id: string`

        The id of the `agent.custom_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

      - `type: "user.custom_tool_result"`

        - `"user.custom_tool_result"`

      - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

        The result content returned by the tool.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

          A block containing a web search result.

          - `citations: object { enabled }`

            Citation settings for a search result.

            - `enabled: boolean`

              Whether citations are enabled for this search result.

          - `content: array of BetaManagedAgentsSearchResultContent`

            Array of text content blocks from the search result.

            - `text: string`

              The text content.

            - `type: "text"`

              - `"text"`

          - `source: string`

            The URL source of the search result.

          - `title: string`

            The title of the search result.

          - `type: "search_result"`

            - `"search_result"`

      - `is_error: optional boolean`

        Whether the tool execution resulted in an error.

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

      - `session_thread_id: optional string`

        Routes this result to a subagent thread. Copy from the `agent.custom_tool_use` event's `session_thread_id`.

    - `beta_managed_agents_user_define_outcome_event: object { id, description, max_iterations, 4 more }`

      Echo of a `user.define_outcome` input event. Carries the server-generated `outcome_id` that subsequent `span.outcome_evaluation_*` events reference.

      - `id: string`

        Unique identifier for this event.

      - `description: string`

        What the agent should produce. Copied from the input event.

      - `max_iterations: number`

        Evaluate-then-revise cycles before giving up. Default 3, max 20.

      - `outcome_id: string`

        Server-generated `outc_` ID for this outcome. Referenced by `span.outcome_evaluation_*` events and the session's `outcome_evaluations` list.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `rubric: BetaManagedAgentsFileRubric or BetaManagedAgentsTextRubric`

        Rubric for grading the quality of an outcome.

        - `beta_managed_agents_file_rubric: object { file_id, type }`

          Rubric referenced by a file uploaded via the Files API.

          - `file_id: string`

            ID of the rubric file.

          - `type: "file"`

            - `"file"`

        - `beta_managed_agents_text_rubric: object { content, type }`

          Rubric content provided inline as text.

          - `content: string`

            Rubric content. Plain text or markdown — the grader treats it as freeform text.

          - `type: "text"`

            - `"text"`

      - `type: "user.define_outcome"`

        - `"user.define_outcome"`

    - `beta_managed_agents_user_tool_result_event: object { id, tool_use_id, type, 4 more }`

      Event sent by the client providing the result of an agent-toolset tool execution. Only valid on `self_hosted` environments, where sandbox-routed tools are executed by the client rather than the server.

      - `id: string`

        Unique identifier for this event.

      - `tool_use_id: string`

        The id of the `agent.tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

      - `type: "user.tool_result"`

        - `"user.tool_result"`

      - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

        The result content returned by the tool.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

          A block containing a web search result.

      - `is_error: optional boolean`

        Whether the tool execution resulted in an error.

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

      - `session_thread_id: optional string`

        Routes this result to a subagent thread. Copy from the `agent.tool_use` event's `session_thread_id`.

    - `beta_managed_agents_system_message_event: object { id, content, type, processed_at }`

      A mid-conversation system message event. Carries system-role content that is appended to the session as a `role: "system"` turn.

      - `id: string`

        Unique identifier for this event.

      - `content: array of BetaManagedAgentsSystemContentBlock`

        System content blocks. Text-only.

        - `text: string`

          The text content.

        - `type: "text"`

          - `"text"`

      - `type: "system.message"`

        - `"system.message"`

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

### Beta Managed Agents Session Deleted Event

- `beta_managed_agents_session_deleted_event: object { id, processed_at, type }`

  Emitted when a session has been deleted. Terminates any active event stream — no further events will be emitted for this session.

  - `id: string`

    Unique identifier for this event.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `type: "session.deleted"`

    - `"session.deleted"`

### Beta Managed Agents Session End Turn

- `beta_managed_agents_session_end_turn: object { type }`

  The agent completed its turn naturally and is ready for the next user message.

  - `type: "end_turn"`

    - `"end_turn"`

### Beta Managed Agents Session Error Event

- `beta_managed_agents_session_error_event: object { id, error, processed_at, type }`

  An error event indicating a problem occurred during session execution.

  - `id: string`

    Unique identifier for this event.

  - `error: BetaManagedAgentsUnknownError or BetaManagedAgentsModelOverloadedError or BetaManagedAgentsModelRateLimitedError or 5 more`

    An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

    - `beta_managed_agents_unknown_error: object { message, retry_status, type }`

      An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

      - `message: string`

        Human-readable error description.

      - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

        What the client should do next in response to this error.

        - `beta_managed_agents_retry_status_retrying: object { type }`

          The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `type: "retrying"`

            - `"retrying"`

        - `beta_managed_agents_retry_status_exhausted: object { type }`

          This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `type: "exhausted"`

            - `"exhausted"`

        - `beta_managed_agents_retry_status_terminal: object { type }`

          The session encountered a terminal error and will transition to `terminated` state.

          - `type: "terminal"`

            - `"terminal"`

      - `type: "unknown_error"`

        - `"unknown_error"`

    - `beta_managed_agents_model_overloaded_error: object { message, retry_status, type }`

      The model is currently overloaded. Emitted after automatic retries are exhausted.

      - `message: string`

        Human-readable error description.

      - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

        What the client should do next in response to this error.

        - `beta_managed_agents_retry_status_retrying: object { type }`

          The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

        - `beta_managed_agents_retry_status_exhausted: object { type }`

          This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

        - `beta_managed_agents_retry_status_terminal: object { type }`

          The session encountered a terminal error and will transition to `terminated` state.

      - `type: "model_overloaded_error"`

        - `"model_overloaded_error"`

    - `beta_managed_agents_model_rate_limited_error: object { message, retry_status, type }`

      The model request was rate-limited.

      - `message: string`

        Human-readable error description.

      - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

        What the client should do next in response to this error.

        - `beta_managed_agents_retry_status_retrying: object { type }`

          The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

        - `beta_managed_agents_retry_status_exhausted: object { type }`

          This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

        - `beta_managed_agents_retry_status_terminal: object { type }`

          The session encountered a terminal error and will transition to `terminated` state.

      - `type: "model_rate_limited_error"`

        - `"model_rate_limited_error"`

    - `beta_managed_agents_model_request_failed_error: object { message, retry_status, type }`

      A model request failed for a reason other than overload or rate-limiting.

      - `message: string`

        Human-readable error description.

      - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

        What the client should do next in response to this error.

        - `beta_managed_agents_retry_status_retrying: object { type }`

          The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

        - `beta_managed_agents_retry_status_exhausted: object { type }`

          This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

        - `beta_managed_agents_retry_status_terminal: object { type }`

          The session encountered a terminal error and will transition to `terminated` state.

      - `type: "model_request_failed_error"`

        - `"model_request_failed_error"`

    - `beta_managed_agents_mcp_connection_failed_error: object { mcp_server_name, message, retry_status, type }`

      Failed to connect to an MCP server.

      - `mcp_server_name: string`

        Name of the MCP server that failed to connect.

      - `message: string`

        Human-readable error description.

      - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

        What the client should do next in response to this error.

        - `beta_managed_agents_retry_status_retrying: object { type }`

          The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

        - `beta_managed_agents_retry_status_exhausted: object { type }`

          This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

        - `beta_managed_agents_retry_status_terminal: object { type }`

          The session encountered a terminal error and will transition to `terminated` state.

      - `type: "mcp_connection_failed_error"`

        - `"mcp_connection_failed_error"`

    - `beta_managed_agents_mcp_authentication_failed_error: object { mcp_server_name, message, retry_status, type }`

      Authentication to an MCP server failed.

      - `mcp_server_name: string`

        Name of the MCP server that failed authentication.

      - `message: string`

        Human-readable error description.

      - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

        What the client should do next in response to this error.

        - `beta_managed_agents_retry_status_retrying: object { type }`

          The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

        - `beta_managed_agents_retry_status_exhausted: object { type }`

          This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

        - `beta_managed_agents_retry_status_terminal: object { type }`

          The session encountered a terminal error and will transition to `terminated` state.

      - `type: "mcp_authentication_failed_error"`

        - `"mcp_authentication_failed_error"`

    - `beta_managed_agents_billing_error: object { message, retry_status, type }`

      The caller's organization or workspace cannot make model requests — out of credits or spend limit reached. Retrying with the same credentials will not succeed; the caller must resolve the billing state.

      - `message: string`

        Human-readable error description.

      - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

        What the client should do next in response to this error.

        - `beta_managed_agents_retry_status_retrying: object { type }`

          The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

        - `beta_managed_agents_retry_status_exhausted: object { type }`

          This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

        - `beta_managed_agents_retry_status_terminal: object { type }`

          The session encountered a terminal error and will transition to `terminated` state.

      - `type: "billing_error"`

        - `"billing_error"`

    - `beta_managed_agents_credential_host_unreachable_error: object { credential_id, message, retry_status, 2 more }`

      An `environment_variable` credential's `auth.networking.allowed_hosts` includes a host the environment's network policy does not permit.

      - `credential_id: string`

        ID of the affected credential.

      - `message: string`

        Human-readable error description.

      - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

        What the client should do next in response to this error.

        - `beta_managed_agents_retry_status_retrying: object { type }`

          The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

        - `beta_managed_agents_retry_status_exhausted: object { type }`

          This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

        - `beta_managed_agents_retry_status_terminal: object { type }`

          The session encountered a terminal error and will transition to `terminated` state.

      - `type: "credential_host_unreachable_error"`

        - `"credential_host_unreachable_error"`

      - `vault_id: string`

        ID of the vault containing the affected credential.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `type: "session.error"`

    - `"session.error"`

### Beta Managed Agents Session Event

- `beta_managed_agents_session_event: BetaManagedAgentsUserMessageEvent or BetaManagedAgentsUserInterruptEvent or BetaManagedAgentsUserToolConfirmationEvent or 31 more`

  Union type for all event types in a session.

  - `beta_managed_agents_user_message_event: object { id, content, type, processed_at }`

    A user message event in the session conversation.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

      Array of content blocks comprising the user message.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

        - `text: string`

          The text content.

        - `type: "text"`

          - `"text"`

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

        - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

          Union type for image source variants.

          - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

            Base64-encoded image data.

            - `data: string`

              Base64-encoded image data.

            - `media_type: string`

              MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

            - `type: "base64"`

              - `"base64"`

          - `beta_managed_agents_url_image_source: object { type, url }`

            Image referenced by URL.

            - `type: "url"`

              - `"url"`

            - `url: string`

              URL of the image to fetch.

          - `beta_managed_agents_file_image_source: object { file_id, type }`

            Image referenced by file ID.

            - `file_id: string`

              ID of a previously uploaded file.

            - `type: "file"`

              - `"file"`

        - `type: "image"`

          - `"image"`

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

          Union type for document source variants.

          - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

            Base64-encoded document data.

            - `data: string`

              Base64-encoded document data.

            - `media_type: string`

              MIME type of the document (e.g., "application/pdf").

            - `type: "base64"`

              - `"base64"`

          - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

            Plain text document content.

            - `data: string`

              The plain text content.

            - `media_type: "text/plain"`

              MIME type of the text content. Must be "text/plain".

              - `"text/plain"`

            - `type: "text"`

              - `"text"`

          - `beta_managed_agents_url_document_source: object { type, url }`

            Document referenced by URL.

            - `type: "url"`

              - `"url"`

            - `url: string`

              URL of the document to fetch.

          - `beta_managed_agents_file_document_source: object { file_id, type }`

            Document referenced by file ID.

            - `file_id: string`

              ID of a previously uploaded file.

            - `type: "file"`

              - `"file"`

        - `type: "document"`

          - `"document"`

        - `context: optional string`

          Additional context about the document for the model.

        - `title: optional string`

          The title of the document.

    - `type: "user.message"`

      - `"user.message"`

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

  - `beta_managed_agents_user_interrupt_event: object { id, type, processed_at, session_thread_id }`

    An interrupt event that pauses agent execution and returns control to the user.

    - `id: string`

      Unique identifier for this event.

    - `type: "user.interrupt"`

      - `"user.interrupt"`

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      If absent, interrupts every non-archived thread in a multiagent session (or the primary alone in a single-agent session). If present, interrupts only the named thread.

  - `beta_managed_agents_user_tool_confirmation_event: object { id, result, tool_use_id, 4 more }`

    A tool confirmation event that approves or denies a pending tool execution.

    - `id: string`

      Unique identifier for this event.

    - `result: "allow" or "deny"`

      UserToolConfirmationResult enum

      - `"allow"`

      - `"deny"`

    - `tool_use_id: string`

      The id of the `agent.tool_use` or `agent.mcp_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: "user.tool_confirmation"`

      - `"user.tool_confirmation"`

    - `deny_message: optional string`

      Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'.

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      When set, the confirmation routes to this subagent's thread rather than the primary. Echo this from the `session_thread_id` on the `agent.tool_use` or `agent.mcp_tool_use` event that prompted the approval.

  - `beta_managed_agents_user_custom_tool_result_event: object { id, custom_tool_use_id, type, 4 more }`

    Event sent by the client providing the result of a custom tool execution.

    - `id: string`

      Unique identifier for this event.

    - `custom_tool_use_id: string`

      The id of the `agent.custom_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: "user.custom_tool_result"`

      - `"user.custom_tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

        - `citations: object { enabled }`

          Citation settings for a search result.

          - `enabled: boolean`

            Whether citations are enabled for this search result.

        - `content: array of BetaManagedAgentsSearchResultContent`

          Array of text content blocks from the search result.

          - `text: string`

            The text content.

          - `type: "text"`

            - `"text"`

        - `source: string`

          The URL source of the search result.

        - `title: string`

          The title of the search result.

        - `type: "search_result"`

          - `"search_result"`

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      Routes this result to a subagent thread. Copy from the `agent.custom_tool_use` event's `session_thread_id`.

  - `beta_managed_agents_agent_custom_tool_use_event: object { id, input, name, 3 more }`

    Event emitted when the agent calls a custom tool. The session goes idle until the client sends a `user.custom_tool_result` event with the result.

    - `id: string`

      Unique identifier for this event.

    - `input: map[unknown]`

      Input parameters for the tool call.

    - `name: string`

      Name of the custom tool being called.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.custom_tool_use"`

      - `"agent.custom_tool_use"`

    - `session_thread_id: optional string`

      When set, this event was cross-posted from a subagent's thread to surface its custom tool use on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.custom_tool_result` event to route the result back.

  - `beta_managed_agents_agent_message_event: object { id, content, processed_at, type }`

    An agent response event in the session conversation.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock`

      Array of text blocks comprising the agent response.

      - `text: string`

        The text content.

      - `type: "text"`

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.message"`

      - `"agent.message"`

  - `beta_managed_agents_agent_thinking_event: object { id, processed_at, type }`

    Indicates the agent is making forward progress via extended thinking. A progress signal, not a content carrier.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.thinking"`

      - `"agent.thinking"`

  - `beta_managed_agents_agent_mcp_tool_use_event: object { id, input, mcp_server_name, 5 more }`

    Event emitted when the agent invokes a tool provided by an MCP server.

    - `id: string`

      Unique identifier for this event.

    - `input: map[unknown]`

      Input parameters for the tool call.

    - `mcp_server_name: string`

      Name of the MCP server providing the tool.

    - `name: string`

      Name of the MCP tool being used.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.mcp_tool_use"`

      - `"agent.mcp_tool_use"`

    - `evaluated_permission: optional "allow" or "ask" or "deny"`

      AgentEvaluatedPermission enum

      - `"allow"`

      - `"ask"`

      - `"deny"`

    - `session_thread_id: optional string`

      When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

  - `beta_managed_agents_agent_mcp_tool_result_event: object { id, mcp_tool_use_id, processed_at, 3 more }`

    Event representing the result of an MCP tool execution.

    - `id: string`

      Unique identifier for this event.

    - `mcp_tool_use_id: string`

      The id of the `agent.mcp_tool_use` event this result corresponds to.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.mcp_tool_result"`

      - `"agent.mcp_tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

  - `beta_managed_agents_agent_tool_use_event: object { id, input, name, 4 more }`

    Event emitted when the agent invokes a built-in agent tool.

    - `id: string`

      Unique identifier for this event.

    - `input: map[unknown]`

      Input parameters for the tool call.

    - `name: string`

      Name of the agent tool being used.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.tool_use"`

      - `"agent.tool_use"`

    - `evaluated_permission: optional "allow" or "ask" or "deny"`

      AgentEvaluatedPermission enum

      - `"allow"`

      - `"ask"`

      - `"deny"`

    - `session_thread_id: optional string`

      When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

  - `beta_managed_agents_agent_tool_result_event: object { id, processed_at, tool_use_id, 3 more }`

    Event representing the result of an agent tool execution.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `tool_use_id: string`

      The id of the `agent.tool_use` event this result corresponds to.

    - `type: "agent.tool_result"`

      - `"agent.tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

  - `beta_managed_agents_agent_thread_message_received_event: object { id, content, from_session_thread_id, 3 more }`

    Delivery event written to the target thread's input stream when an agent-to-agent message arrives.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

      Message content blocks.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

    - `from_session_thread_id: string`

      Public `sthr_` ID of the thread that sent the message.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.thread_message_received"`

      - `"agent.thread_message_received"`

    - `from_agent_name: optional string`

      Name of the callable agent this message came from. Absent when received from the primary agent.

  - `beta_managed_agents_agent_thread_message_sent_event: object { id, content, processed_at, 3 more }`

    Observability event emitted to the sender's output stream when an agent-to-agent message is sent.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

      Message content blocks.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `to_session_thread_id: string`

      Public `sthr_` ID of the thread the message was sent to.

    - `type: "agent.thread_message_sent"`

      - `"agent.thread_message_sent"`

    - `to_agent_name: optional string`

      Name of the callable agent this message was sent to. Absent when sent to the primary agent.

  - `beta_managed_agents_agent_thread_context_compacted_event: object { id, processed_at, type }`

    Indicates that context compaction (summarization) occurred during the session.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.thread_context_compacted"`

      - `"agent.thread_context_compacted"`

  - `beta_managed_agents_session_error_event: object { id, error, processed_at, type }`

    An error event indicating a problem occurred during session execution.

    - `id: string`

      Unique identifier for this event.

    - `error: BetaManagedAgentsUnknownError or BetaManagedAgentsModelOverloadedError or BetaManagedAgentsModelRateLimitedError or 5 more`

      An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

      - `beta_managed_agents_unknown_error: object { message, retry_status, type }`

        An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `type: "retrying"`

              - `"retrying"`

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `type: "exhausted"`

              - `"exhausted"`

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

            - `type: "terminal"`

              - `"terminal"`

        - `type: "unknown_error"`

          - `"unknown_error"`

      - `beta_managed_agents_model_overloaded_error: object { message, retry_status, type }`

        The model is currently overloaded. Emitted after automatic retries are exhausted.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "model_overloaded_error"`

          - `"model_overloaded_error"`

      - `beta_managed_agents_model_rate_limited_error: object { message, retry_status, type }`

        The model request was rate-limited.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "model_rate_limited_error"`

          - `"model_rate_limited_error"`

      - `beta_managed_agents_model_request_failed_error: object { message, retry_status, type }`

        A model request failed for a reason other than overload or rate-limiting.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "model_request_failed_error"`

          - `"model_request_failed_error"`

      - `beta_managed_agents_mcp_connection_failed_error: object { mcp_server_name, message, retry_status, type }`

        Failed to connect to an MCP server.

        - `mcp_server_name: string`

          Name of the MCP server that failed to connect.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "mcp_connection_failed_error"`

          - `"mcp_connection_failed_error"`

      - `beta_managed_agents_mcp_authentication_failed_error: object { mcp_server_name, message, retry_status, type }`

        Authentication to an MCP server failed.

        - `mcp_server_name: string`

          Name of the MCP server that failed authentication.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "mcp_authentication_failed_error"`

          - `"mcp_authentication_failed_error"`

      - `beta_managed_agents_billing_error: object { message, retry_status, type }`

        The caller's organization or workspace cannot make model requests — out of credits or spend limit reached. Retrying with the same credentials will not succeed; the caller must resolve the billing state.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "billing_error"`

          - `"billing_error"`

      - `beta_managed_agents_credential_host_unreachable_error: object { credential_id, message, retry_status, 2 more }`

        An `environment_variable` credential's `auth.networking.allowed_hosts` includes a host the environment's network policy does not permit.

        - `credential_id: string`

          ID of the affected credential.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "credential_host_unreachable_error"`

          - `"credential_host_unreachable_error"`

        - `vault_id: string`

          ID of the vault containing the affected credential.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.error"`

      - `"session.error"`

  - `beta_managed_agents_session_status_rescheduled_event: object { id, processed_at, type }`

    Indicates the session is recovering from an error state and is rescheduled for execution.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.status_rescheduled"`

      - `"session.status_rescheduled"`

  - `beta_managed_agents_session_status_running_event: object { id, processed_at, type }`

    Indicates the session is actively running and the agent is working.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.status_running"`

      - `"session.status_running"`

  - `beta_managed_agents_session_status_idle_event: object { id, processed_at, stop_reason, type }`

    Indicates the agent has paused and is awaiting user input.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `stop_reason: BetaManagedAgentsSessionEndTurn or BetaManagedAgentsSessionRequiresAction or BetaManagedAgentsSessionRetriesExhausted`

      The agent completed its turn naturally and is ready for the next user message.

      - `beta_managed_agents_session_end_turn: object { type }`

        The agent completed its turn naturally and is ready for the next user message.

        - `type: "end_turn"`

          - `"end_turn"`

      - `beta_managed_agents_session_requires_action: object { event_ids, type }`

        The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

        - `event_ids: array of string`

          The ids of events the agent is blocked on. Resolving fewer than all re-emits `session.status_idle` with the remainder.

        - `type: "requires_action"`

          - `"requires_action"`

      - `beta_managed_agents_session_retries_exhausted: object { type }`

        The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

        - `type: "retries_exhausted"`

          - `"retries_exhausted"`

    - `type: "session.status_idle"`

      - `"session.status_idle"`

  - `beta_managed_agents_session_status_terminated_event: object { id, processed_at, type }`

    Indicates the session has terminated, either due to an error or completion.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.status_terminated"`

      - `"session.status_terminated"`

  - `beta_managed_agents_session_thread_created_event: object { id, agent_name, processed_at, 2 more }`

    Emitted when a subagent is spawned as a new thread. Written to the parent thread's output stream so clients observing the session see child creation.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the callable agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public `sthr_` ID of the newly created thread.

    - `type: "session.thread_created"`

      - `"session.thread_created"`

  - `beta_managed_agents_span_outcome_evaluation_start_event: object { id, iteration, outcome_id, 2 more }`

    Emitted when an outcome evaluation cycle begins.

    - `id: string`

      Unique identifier for this event.

    - `iteration: number`

      0-indexed revision cycle. 0 is the first evaluation; 1 is the re-evaluation after the first revision; etc.

    - `outcome_id: string`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.outcome_evaluation_start"`

      - `"span.outcome_evaluation_start"`

  - `beta_managed_agents_span_outcome_evaluation_end_event: object { id, explanation, iteration, 6 more }`

    Emitted when an outcome evaluation cycle completes. Carries the verdict and aggregate token usage. A verdict of `needs_revision` means another evaluation cycle follows; `satisfied`, `max_iterations_reached`, `failed`, or `interrupted` are terminal — no further evaluation cycles follow.

    - `id: string`

      Unique identifier for this event.

    - `explanation: string`

      Human-readable explanation of the verdict. For `needs_revision`, describes which criteria failed and why.

    - `iteration: number`

      0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

    - `outcome_evaluation_start_id: string`

      The id of the corresponding `span.outcome_evaluation_start` event.

    - `outcome_id: string`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `result: string`

      Evaluation verdict. 'satisfied': criteria met, session goes idle. 'needs_revision': criteria not met, another revision cycle follows. 'max_iterations_reached': evaluation budget exhausted with criteria still unmet — one final acknowledgment turn follows before the session goes idle, but no further evaluation runs. 'failed': grader determined the rubric does not apply to the deliverables. 'interrupted': user sent an interrupt while evaluation was in progress.

    - `type: "span.outcome_evaluation_end"`

      - `"span.outcome_evaluation_end"`

    - `usage: object { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }`

      Token usage for a single model request.

      - `cache_creation_input_tokens: number`

        Tokens used to create prompt cache in this request.

      - `cache_read_input_tokens: number`

        Tokens read from prompt cache in this request.

      - `input_tokens: number`

        Input tokens consumed by this request.

      - `output_tokens: number`

        Output tokens generated by this request.

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `"standard"`

        - `"fast"`

  - `beta_managed_agents_span_model_request_start_event: object { id, processed_at, type }`

    Emitted when a model request is initiated by the agent.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.model_request_start"`

      - `"span.model_request_start"`

  - `beta_managed_agents_span_model_request_end_event: object { id, is_error, model_request_start_id, 3 more }`

    Emitted when a model request completes.

    - `id: string`

      Unique identifier for this event.

    - `is_error: boolean`

      Whether the model request resulted in an error.

    - `model_request_start_id: string`

      The id of the corresponding `span.model_request_start` event.

    - `model_usage: object { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }`

      Token usage for a single model request.

      - `cache_creation_input_tokens: number`

        Tokens used to create prompt cache in this request.

      - `cache_read_input_tokens: number`

        Tokens read from prompt cache in this request.

      - `input_tokens: number`

        Input tokens consumed by this request.

      - `output_tokens: number`

        Output tokens generated by this request.

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.model_request_end"`

      - `"span.model_request_end"`

  - `beta_managed_agents_span_outcome_evaluation_ongoing_event: object { id, iteration, outcome_id, 2 more }`

    Periodic heartbeat emitted while an outcome evaluation cycle is in progress. Distinguishes 'evaluation is actively running' from 'evaluation is stuck' between the corresponding `span.outcome_evaluation_start` and `span.outcome_evaluation_end` events.

    - `id: string`

      Unique identifier for this event.

    - `iteration: number`

      0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

    - `outcome_id: string`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.outcome_evaluation_ongoing"`

      - `"span.outcome_evaluation_ongoing"`

  - `beta_managed_agents_user_define_outcome_event: object { id, description, max_iterations, 4 more }`

    Echo of a `user.define_outcome` input event. Carries the server-generated `outcome_id` that subsequent `span.outcome_evaluation_*` events reference.

    - `id: string`

      Unique identifier for this event.

    - `description: string`

      What the agent should produce. Copied from the input event.

    - `max_iterations: number`

      Evaluate-then-revise cycles before giving up. Default 3, max 20.

    - `outcome_id: string`

      Server-generated `outc_` ID for this outcome. Referenced by `span.outcome_evaluation_*` events and the session's `outcome_evaluations` list.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `rubric: BetaManagedAgentsFileRubric or BetaManagedAgentsTextRubric`

      Rubric for grading the quality of an outcome.

      - `beta_managed_agents_file_rubric: object { file_id, type }`

        Rubric referenced by a file uploaded via the Files API.

        - `file_id: string`

          ID of the rubric file.

        - `type: "file"`

          - `"file"`

      - `beta_managed_agents_text_rubric: object { content, type }`

        Rubric content provided inline as text.

        - `content: string`

          Rubric content. Plain text or markdown — the grader treats it as freeform text.

        - `type: "text"`

          - `"text"`

    - `type: "user.define_outcome"`

      - `"user.define_outcome"`

  - `beta_managed_agents_session_deleted_event: object { id, processed_at, type }`

    Emitted when a session has been deleted. Terminates any active event stream — no further events will be emitted for this session.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.deleted"`

      - `"session.deleted"`

  - `beta_managed_agents_session_thread_status_running_event: object { id, agent_name, processed_at, 2 more }`

    A session thread has begun executing. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that started running.

    - `type: "session.thread_status_running"`

      - `"session.thread_status_running"`

  - `beta_managed_agents_session_thread_status_idle_event: object { id, agent_name, processed_at, 3 more }`

    A session thread has yielded and is awaiting input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that went idle.

    - `stop_reason: BetaManagedAgentsSessionEndTurn or BetaManagedAgentsSessionRequiresAction or BetaManagedAgentsSessionRetriesExhausted`

      The agent completed its turn naturally and is ready for the next user message.

      - `beta_managed_agents_session_end_turn: object { type }`

        The agent completed its turn naturally and is ready for the next user message.

      - `beta_managed_agents_session_requires_action: object { event_ids, type }`

        The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

      - `beta_managed_agents_session_retries_exhausted: object { type }`

        The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

    - `type: "session.thread_status_idle"`

      - `"session.thread_status_idle"`

  - `beta_managed_agents_session_thread_status_terminated_event: object { id, agent_name, processed_at, 2 more }`

    A session thread has terminated and will accept no further input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that terminated.

    - `type: "session.thread_status_terminated"`

      - `"session.thread_status_terminated"`

  - `beta_managed_agents_user_tool_result_event: object { id, tool_use_id, type, 4 more }`

    Event sent by the client providing the result of an agent-toolset tool execution. Only valid on `self_hosted` environments, where sandbox-routed tools are executed by the client rather than the server.

    - `id: string`

      Unique identifier for this event.

    - `tool_use_id: string`

      The id of the `agent.tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: "user.tool_result"`

      - `"user.tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      Routes this result to a subagent thread. Copy from the `agent.tool_use` event's `session_thread_id`.

  - `beta_managed_agents_session_thread_status_rescheduled_event: object { id, agent_name, processed_at, 2 more }`

    A session thread hit a transient error and is retrying automatically. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that is retrying.

    - `type: "session.thread_status_rescheduled"`

      - `"session.thread_status_rescheduled"`

  - `beta_managed_agents_session_updated_event: object { id, processed_at, type, 3 more }`

    Emitted when an UpdateSession request changed at least one field. Carries only the fields that changed; absent fields were not part of the update. The new configuration applies from the next turn.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.updated"`

      - `"session.updated"`

    - `agent: optional object { id, description, mcp_servers, 8 more }`

      Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time.

      - `id: string`

      - `description: string`

      - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

        - `name: string`

        - `type: "url"`

          - `"url"`

        - `url: string`

      - `model: object { id, speed }`

        Model identifier and configuration.

        - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

          The model that will power your agent.

          See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

          - `"claude-fable-5"`

            Next generation of intelligence for the hardest knowledge work and coding problems

          - `"claude-opus-4-8"`

            Frontier intelligence for long-running agents and coding

          - `"claude-opus-4-7"`

            Frontier intelligence for long-running agents and coding

          - `"claude-opus-4-6"`

            Most intelligent model for building agents and coding

          - `"claude-sonnet-4-6"`

            Best combination of speed and intelligence

          - `"claude-haiku-4-5"`

            Fastest model with near-frontier intelligence

          - `"claude-haiku-4-5-20251001"`

            Fastest model with near-frontier intelligence

          - `"claude-opus-4-5"`

            Premium model combining maximum intelligence with practical performance

          - `"claude-opus-4-5-20251101"`

            Premium model combining maximum intelligence with practical performance

          - `"claude-sonnet-4-5"`

            High-performance model for agents and coding

          - `"claude-sonnet-4-5-20250929"`

            High-performance model for agents and coding

        - `speed: optional "standard" or "fast"`

          Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

          - `"standard"`

          - `"fast"`

      - `multiagent: object { agents, type }`

        Resolved coordinator topology with full agent definitions for each roster member.

        - `agents: array of BetaManagedAgentsSessionThreadAgent`

          Full `agent` definitions the coordinator may spawn as session threads.

          - `id: string`

          - `description: string`

          - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

            - `name: string`

            - `type: "url"`

            - `url: string`

          - `model: object { id, speed }`

            Model identifier and configuration.

            - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

              The model that will power your agent.

              See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

            - `speed: optional "standard" or "fast"`

              Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

          - `name: string`

          - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

            - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

              A resolved Anthropic-managed skill.

              - `skill_id: string`

              - `type: "anthropic"`

                - `"anthropic"`

              - `version: string`

            - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

              A resolved user-created custom skill.

              - `skill_id: string`

              - `type: "custom"`

                - `"custom"`

              - `version: string`

          - `system: string`

          - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

            - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

              - `configs: array of BetaManagedAgentsAgentToolConfig`

                - `enabled: boolean`

                - `name: "bash" or "edit" or "read" or 5 more`

                  Built-in agent tool identifier.

                  - `"bash"`

                  - `"edit"`

                  - `"read"`

                  - `"write"`

                  - `"glob"`

                  - `"grep"`

                  - `"web_fetch"`

                  - `"web_search"`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                    - `type: "always_allow"`

                      - `"always_allow"`

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

                    - `type: "always_ask"`

                      - `"always_ask"`

              - `default_config: object { enabled, permission_policy }`

                Resolved default configuration for agent tools.

                - `enabled: boolean`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

              - `type: "agent_toolset_20260401"`

                - `"agent_toolset_20260401"`

            - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

              - `configs: array of BetaManagedAgentsMCPToolConfig`

                - `enabled: boolean`

                - `name: string`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

              - `default_config: object { enabled, permission_policy }`

                Resolved default configuration for all tools from an MCP server.

                - `enabled: boolean`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

              - `mcp_server_name: string`

              - `type: "mcp_toolset"`

                - `"mcp_toolset"`

            - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

              A custom tool as returned in API responses.

              - `description: string`

              - `input_schema: object { type, properties, required }`

                JSON Schema for custom tool input parameters.

                - `type: "object"`

                - `properties: optional map[unknown]`

                - `required: optional array of string`

              - `name: string`

              - `type: "custom"`

                - `"custom"`

          - `type: "agent"`

            - `"agent"`

          - `version: number`

        - `type: "coordinator"`

          - `"coordinator"`

      - `name: string`

      - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

        - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

          A resolved Anthropic-managed skill.

        - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

          A resolved user-created custom skill.

      - `system: string`

      - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

        - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

        - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

        - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

          A custom tool as returned in API responses.

      - `type: "agent"`

        - `"agent"`

      - `version: number`

    - `metadata: optional map[string]`

      The session's full metadata bag after the update. Present when the update set non-empty metadata; absent when metadata was unchanged or cleared to empty.

    - `title: optional string`

      The session's new title. Present only when the update changed it.

  - `beta_managed_agents_system_message_event: object { id, content, type, processed_at }`

    A mid-conversation system message event. Carries system-role content that is appended to the session as a `role: "system"` turn.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsSystemContentBlock`

      System content blocks. Text-only.

      - `text: string`

        The text content.

      - `type: "text"`

        - `"text"`

    - `type: "system.message"`

      - `"system.message"`

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

### Beta Managed Agents Session Requires Action

- `beta_managed_agents_session_requires_action: object { event_ids, type }`

  The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

  - `event_ids: array of string`

    The ids of events the agent is blocked on. Resolving fewer than all re-emits `session.status_idle` with the remainder.

  - `type: "requires_action"`

    - `"requires_action"`

### Beta Managed Agents Session Retries Exhausted

- `beta_managed_agents_session_retries_exhausted: object { type }`

  The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

  - `type: "retries_exhausted"`

    - `"retries_exhausted"`

### Beta Managed Agents Session Status Idle Event

- `beta_managed_agents_session_status_idle_event: object { id, processed_at, stop_reason, type }`

  Indicates the agent has paused and is awaiting user input.

  - `id: string`

    Unique identifier for this event.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `stop_reason: BetaManagedAgentsSessionEndTurn or BetaManagedAgentsSessionRequiresAction or BetaManagedAgentsSessionRetriesExhausted`

    The agent completed its turn naturally and is ready for the next user message.

    - `beta_managed_agents_session_end_turn: object { type }`

      The agent completed its turn naturally and is ready for the next user message.

      - `type: "end_turn"`

        - `"end_turn"`

    - `beta_managed_agents_session_requires_action: object { event_ids, type }`

      The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

      - `event_ids: array of string`

        The ids of events the agent is blocked on. Resolving fewer than all re-emits `session.status_idle` with the remainder.

      - `type: "requires_action"`

        - `"requires_action"`

    - `beta_managed_agents_session_retries_exhausted: object { type }`

      The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

      - `type: "retries_exhausted"`

        - `"retries_exhausted"`

  - `type: "session.status_idle"`

    - `"session.status_idle"`

### Beta Managed Agents Session Status Rescheduled Event

- `beta_managed_agents_session_status_rescheduled_event: object { id, processed_at, type }`

  Indicates the session is recovering from an error state and is rescheduled for execution.

  - `id: string`

    Unique identifier for this event.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `type: "session.status_rescheduled"`

    - `"session.status_rescheduled"`

### Beta Managed Agents Session Status Running Event

- `beta_managed_agents_session_status_running_event: object { id, processed_at, type }`

  Indicates the session is actively running and the agent is working.

  - `id: string`

    Unique identifier for this event.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `type: "session.status_running"`

    - `"session.status_running"`

### Beta Managed Agents Session Status Terminated Event

- `beta_managed_agents_session_status_terminated_event: object { id, processed_at, type }`

  Indicates the session has terminated, either due to an error or completion.

  - `id: string`

    Unique identifier for this event.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `type: "session.status_terminated"`

    - `"session.status_terminated"`

### Beta Managed Agents Session Thread Created Event

- `beta_managed_agents_session_thread_created_event: object { id, agent_name, processed_at, 2 more }`

  Emitted when a subagent is spawned as a new thread. Written to the parent thread's output stream so clients observing the session see child creation.

  - `id: string`

    Unique identifier for this event.

  - `agent_name: string`

    Name of the callable agent the thread runs.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `session_thread_id: string`

    Public `sthr_` ID of the newly created thread.

  - `type: "session.thread_created"`

    - `"session.thread_created"`

### Beta Managed Agents Session Thread Status Idle Event

- `beta_managed_agents_session_thread_status_idle_event: object { id, agent_name, processed_at, 3 more }`

  A session thread has yielded and is awaiting input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

  - `id: string`

    Unique identifier for this event.

  - `agent_name: string`

    Name of the agent the thread runs.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `session_thread_id: string`

    Public sthr_ ID of the thread that went idle.

  - `stop_reason: BetaManagedAgentsSessionEndTurn or BetaManagedAgentsSessionRequiresAction or BetaManagedAgentsSessionRetriesExhausted`

    The agent completed its turn naturally and is ready for the next user message.

    - `beta_managed_agents_session_end_turn: object { type }`

      The agent completed its turn naturally and is ready for the next user message.

      - `type: "end_turn"`

        - `"end_turn"`

    - `beta_managed_agents_session_requires_action: object { event_ids, type }`

      The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

      - `event_ids: array of string`

        The ids of events the agent is blocked on. Resolving fewer than all re-emits `session.status_idle` with the remainder.

      - `type: "requires_action"`

        - `"requires_action"`

    - `beta_managed_agents_session_retries_exhausted: object { type }`

      The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

      - `type: "retries_exhausted"`

        - `"retries_exhausted"`

  - `type: "session.thread_status_idle"`

    - `"session.thread_status_idle"`

### Beta Managed Agents Session Thread Status Rescheduled Event

- `beta_managed_agents_session_thread_status_rescheduled_event: object { id, agent_name, processed_at, 2 more }`

  A session thread hit a transient error and is retrying automatically. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

  - `id: string`

    Unique identifier for this event.

  - `agent_name: string`

    Name of the agent the thread runs.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `session_thread_id: string`

    Public sthr_ ID of the thread that is retrying.

  - `type: "session.thread_status_rescheduled"`

    - `"session.thread_status_rescheduled"`

### Beta Managed Agents Session Thread Status Running Event

- `beta_managed_agents_session_thread_status_running_event: object { id, agent_name, processed_at, 2 more }`

  A session thread has begun executing. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

  - `id: string`

    Unique identifier for this event.

  - `agent_name: string`

    Name of the agent the thread runs.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `session_thread_id: string`

    Public sthr_ ID of the thread that started running.

  - `type: "session.thread_status_running"`

    - `"session.thread_status_running"`

### Beta Managed Agents Session Thread Status Terminated Event

- `beta_managed_agents_session_thread_status_terminated_event: object { id, agent_name, processed_at, 2 more }`

  A session thread has terminated and will accept no further input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

  - `id: string`

    Unique identifier for this event.

  - `agent_name: string`

    Name of the agent the thread runs.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `session_thread_id: string`

    Public sthr_ ID of the thread that terminated.

  - `type: "session.thread_status_terminated"`

    - `"session.thread_status_terminated"`

### Beta Managed Agents Span Model Request End Event

- `beta_managed_agents_span_model_request_end_event: object { id, is_error, model_request_start_id, 3 more }`

  Emitted when a model request completes.

  - `id: string`

    Unique identifier for this event.

  - `is_error: boolean`

    Whether the model request resulted in an error.

  - `model_request_start_id: string`

    The id of the corresponding `span.model_request_start` event.

  - `model_usage: object { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }`

    Token usage for a single model request.

    - `cache_creation_input_tokens: number`

      Tokens used to create prompt cache in this request.

    - `cache_read_input_tokens: number`

      Tokens read from prompt cache in this request.

    - `input_tokens: number`

      Input tokens consumed by this request.

    - `output_tokens: number`

      Output tokens generated by this request.

    - `speed: optional "standard" or "fast"`

      Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

      - `"standard"`

      - `"fast"`

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `type: "span.model_request_end"`

    - `"span.model_request_end"`

### Beta Managed Agents Span Model Request Start Event

- `beta_managed_agents_span_model_request_start_event: object { id, processed_at, type }`

  Emitted when a model request is initiated by the agent.

  - `id: string`

    Unique identifier for this event.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `type: "span.model_request_start"`

    - `"span.model_request_start"`

### Beta Managed Agents Span Model Usage

- `beta_managed_agents_span_model_usage: object { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }`

  Token usage for a single model request.

  - `cache_creation_input_tokens: number`

    Tokens used to create prompt cache in this request.

  - `cache_read_input_tokens: number`

    Tokens read from prompt cache in this request.

  - `input_tokens: number`

    Input tokens consumed by this request.

  - `output_tokens: number`

    Output tokens generated by this request.

  - `speed: optional "standard" or "fast"`

    Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

    - `"standard"`

    - `"fast"`

### Beta Managed Agents Span Outcome Evaluation End Event

- `beta_managed_agents_span_outcome_evaluation_end_event: object { id, explanation, iteration, 6 more }`

  Emitted when an outcome evaluation cycle completes. Carries the verdict and aggregate token usage. A verdict of `needs_revision` means another evaluation cycle follows; `satisfied`, `max_iterations_reached`, `failed`, or `interrupted` are terminal — no further evaluation cycles follow.

  - `id: string`

    Unique identifier for this event.

  - `explanation: string`

    Human-readable explanation of the verdict. For `needs_revision`, describes which criteria failed and why.

  - `iteration: number`

    0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

  - `outcome_evaluation_start_id: string`

    The id of the corresponding `span.outcome_evaluation_start` event.

  - `outcome_id: string`

    The `outc_` ID of the outcome being evaluated.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `result: string`

    Evaluation verdict. 'satisfied': criteria met, session goes idle. 'needs_revision': criteria not met, another revision cycle follows. 'max_iterations_reached': evaluation budget exhausted with criteria still unmet — one final acknowledgment turn follows before the session goes idle, but no further evaluation runs. 'failed': grader determined the rubric does not apply to the deliverables. 'interrupted': user sent an interrupt while evaluation was in progress.

  - `type: "span.outcome_evaluation_end"`

    - `"span.outcome_evaluation_end"`

  - `usage: object { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }`

    Token usage for a single model request.

    - `cache_creation_input_tokens: number`

      Tokens used to create prompt cache in this request.

    - `cache_read_input_tokens: number`

      Tokens read from prompt cache in this request.

    - `input_tokens: number`

      Input tokens consumed by this request.

    - `output_tokens: number`

      Output tokens generated by this request.

    - `speed: optional "standard" or "fast"`

      Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

      - `"standard"`

      - `"fast"`

### Beta Managed Agents Span Outcome Evaluation Ongoing Event

- `beta_managed_agents_span_outcome_evaluation_ongoing_event: object { id, iteration, outcome_id, 2 more }`

  Periodic heartbeat emitted while an outcome evaluation cycle is in progress. Distinguishes 'evaluation is actively running' from 'evaluation is stuck' between the corresponding `span.outcome_evaluation_start` and `span.outcome_evaluation_end` events.

  - `id: string`

    Unique identifier for this event.

  - `iteration: number`

    0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

  - `outcome_id: string`

    The `outc_` ID of the outcome being evaluated.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `type: "span.outcome_evaluation_ongoing"`

    - `"span.outcome_evaluation_ongoing"`

### Beta Managed Agents Span Outcome Evaluation Start Event

- `beta_managed_agents_span_outcome_evaluation_start_event: object { id, iteration, outcome_id, 2 more }`

  Emitted when an outcome evaluation cycle begins.

  - `id: string`

    Unique identifier for this event.

  - `iteration: number`

    0-indexed revision cycle. 0 is the first evaluation; 1 is the re-evaluation after the first revision; etc.

  - `outcome_id: string`

    The `outc_` ID of the outcome being evaluated.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `type: "span.outcome_evaluation_start"`

    - `"span.outcome_evaluation_start"`

### Beta Managed Agents Stream Session Events

- `beta_managed_agents_stream_session_events: BetaManagedAgentsUserMessageEvent or BetaManagedAgentsUserInterruptEvent or BetaManagedAgentsUserToolConfirmationEvent or 31 more`

  Server-sent event in the session stream.

  - `beta_managed_agents_user_message_event: object { id, content, type, processed_at }`

    A user message event in the session conversation.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

      Array of content blocks comprising the user message.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

        - `text: string`

          The text content.

        - `type: "text"`

          - `"text"`

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

        - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

          Union type for image source variants.

          - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

            Base64-encoded image data.

            - `data: string`

              Base64-encoded image data.

            - `media_type: string`

              MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

            - `type: "base64"`

              - `"base64"`

          - `beta_managed_agents_url_image_source: object { type, url }`

            Image referenced by URL.

            - `type: "url"`

              - `"url"`

            - `url: string`

              URL of the image to fetch.

          - `beta_managed_agents_file_image_source: object { file_id, type }`

            Image referenced by file ID.

            - `file_id: string`

              ID of a previously uploaded file.

            - `type: "file"`

              - `"file"`

        - `type: "image"`

          - `"image"`

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

          Union type for document source variants.

          - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

            Base64-encoded document data.

            - `data: string`

              Base64-encoded document data.

            - `media_type: string`

              MIME type of the document (e.g., "application/pdf").

            - `type: "base64"`

              - `"base64"`

          - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

            Plain text document content.

            - `data: string`

              The plain text content.

            - `media_type: "text/plain"`

              MIME type of the text content. Must be "text/plain".

              - `"text/plain"`

            - `type: "text"`

              - `"text"`

          - `beta_managed_agents_url_document_source: object { type, url }`

            Document referenced by URL.

            - `type: "url"`

              - `"url"`

            - `url: string`

              URL of the document to fetch.

          - `beta_managed_agents_file_document_source: object { file_id, type }`

            Document referenced by file ID.

            - `file_id: string`

              ID of a previously uploaded file.

            - `type: "file"`

              - `"file"`

        - `type: "document"`

          - `"document"`

        - `context: optional string`

          Additional context about the document for the model.

        - `title: optional string`

          The title of the document.

    - `type: "user.message"`

      - `"user.message"`

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

  - `beta_managed_agents_user_interrupt_event: object { id, type, processed_at, session_thread_id }`

    An interrupt event that pauses agent execution and returns control to the user.

    - `id: string`

      Unique identifier for this event.

    - `type: "user.interrupt"`

      - `"user.interrupt"`

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      If absent, interrupts every non-archived thread in a multiagent session (or the primary alone in a single-agent session). If present, interrupts only the named thread.

  - `beta_managed_agents_user_tool_confirmation_event: object { id, result, tool_use_id, 4 more }`

    A tool confirmation event that approves or denies a pending tool execution.

    - `id: string`

      Unique identifier for this event.

    - `result: "allow" or "deny"`

      UserToolConfirmationResult enum

      - `"allow"`

      - `"deny"`

    - `tool_use_id: string`

      The id of the `agent.tool_use` or `agent.mcp_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: "user.tool_confirmation"`

      - `"user.tool_confirmation"`

    - `deny_message: optional string`

      Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'.

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      When set, the confirmation routes to this subagent's thread rather than the primary. Echo this from the `session_thread_id` on the `agent.tool_use` or `agent.mcp_tool_use` event that prompted the approval.

  - `beta_managed_agents_user_custom_tool_result_event: object { id, custom_tool_use_id, type, 4 more }`

    Event sent by the client providing the result of a custom tool execution.

    - `id: string`

      Unique identifier for this event.

    - `custom_tool_use_id: string`

      The id of the `agent.custom_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: "user.custom_tool_result"`

      - `"user.custom_tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

        - `citations: object { enabled }`

          Citation settings for a search result.

          - `enabled: boolean`

            Whether citations are enabled for this search result.

        - `content: array of BetaManagedAgentsSearchResultContent`

          Array of text content blocks from the search result.

          - `text: string`

            The text content.

          - `type: "text"`

            - `"text"`

        - `source: string`

          The URL source of the search result.

        - `title: string`

          The title of the search result.

        - `type: "search_result"`

          - `"search_result"`

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      Routes this result to a subagent thread. Copy from the `agent.custom_tool_use` event's `session_thread_id`.

  - `beta_managed_agents_agent_custom_tool_use_event: object { id, input, name, 3 more }`

    Event emitted when the agent calls a custom tool. The session goes idle until the client sends a `user.custom_tool_result` event with the result.

    - `id: string`

      Unique identifier for this event.

    - `input: map[unknown]`

      Input parameters for the tool call.

    - `name: string`

      Name of the custom tool being called.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.custom_tool_use"`

      - `"agent.custom_tool_use"`

    - `session_thread_id: optional string`

      When set, this event was cross-posted from a subagent's thread to surface its custom tool use on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.custom_tool_result` event to route the result back.

  - `beta_managed_agents_agent_message_event: object { id, content, processed_at, type }`

    An agent response event in the session conversation.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock`

      Array of text blocks comprising the agent response.

      - `text: string`

        The text content.

      - `type: "text"`

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.message"`

      - `"agent.message"`

  - `beta_managed_agents_agent_thinking_event: object { id, processed_at, type }`

    Indicates the agent is making forward progress via extended thinking. A progress signal, not a content carrier.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.thinking"`

      - `"agent.thinking"`

  - `beta_managed_agents_agent_mcp_tool_use_event: object { id, input, mcp_server_name, 5 more }`

    Event emitted when the agent invokes a tool provided by an MCP server.

    - `id: string`

      Unique identifier for this event.

    - `input: map[unknown]`

      Input parameters for the tool call.

    - `mcp_server_name: string`

      Name of the MCP server providing the tool.

    - `name: string`

      Name of the MCP tool being used.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.mcp_tool_use"`

      - `"agent.mcp_tool_use"`

    - `evaluated_permission: optional "allow" or "ask" or "deny"`

      AgentEvaluatedPermission enum

      - `"allow"`

      - `"ask"`

      - `"deny"`

    - `session_thread_id: optional string`

      When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

  - `beta_managed_agents_agent_mcp_tool_result_event: object { id, mcp_tool_use_id, processed_at, 3 more }`

    Event representing the result of an MCP tool execution.

    - `id: string`

      Unique identifier for this event.

    - `mcp_tool_use_id: string`

      The id of the `agent.mcp_tool_use` event this result corresponds to.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.mcp_tool_result"`

      - `"agent.mcp_tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

  - `beta_managed_agents_agent_tool_use_event: object { id, input, name, 4 more }`

    Event emitted when the agent invokes a built-in agent tool.

    - `id: string`

      Unique identifier for this event.

    - `input: map[unknown]`

      Input parameters for the tool call.

    - `name: string`

      Name of the agent tool being used.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.tool_use"`

      - `"agent.tool_use"`

    - `evaluated_permission: optional "allow" or "ask" or "deny"`

      AgentEvaluatedPermission enum

      - `"allow"`

      - `"ask"`

      - `"deny"`

    - `session_thread_id: optional string`

      When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

  - `beta_managed_agents_agent_tool_result_event: object { id, processed_at, tool_use_id, 3 more }`

    Event representing the result of an agent tool execution.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `tool_use_id: string`

      The id of the `agent.tool_use` event this result corresponds to.

    - `type: "agent.tool_result"`

      - `"agent.tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

  - `beta_managed_agents_agent_thread_message_received_event: object { id, content, from_session_thread_id, 3 more }`

    Delivery event written to the target thread's input stream when an agent-to-agent message arrives.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

      Message content blocks.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

    - `from_session_thread_id: string`

      Public `sthr_` ID of the thread that sent the message.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.thread_message_received"`

      - `"agent.thread_message_received"`

    - `from_agent_name: optional string`

      Name of the callable agent this message came from. Absent when received from the primary agent.

  - `beta_managed_agents_agent_thread_message_sent_event: object { id, content, processed_at, 3 more }`

    Observability event emitted to the sender's output stream when an agent-to-agent message is sent.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

      Message content blocks.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `to_session_thread_id: string`

      Public `sthr_` ID of the thread the message was sent to.

    - `type: "agent.thread_message_sent"`

      - `"agent.thread_message_sent"`

    - `to_agent_name: optional string`

      Name of the callable agent this message was sent to. Absent when sent to the primary agent.

  - `beta_managed_agents_agent_thread_context_compacted_event: object { id, processed_at, type }`

    Indicates that context compaction (summarization) occurred during the session.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.thread_context_compacted"`

      - `"agent.thread_context_compacted"`

  - `beta_managed_agents_session_error_event: object { id, error, processed_at, type }`

    An error event indicating a problem occurred during session execution.

    - `id: string`

      Unique identifier for this event.

    - `error: BetaManagedAgentsUnknownError or BetaManagedAgentsModelOverloadedError or BetaManagedAgentsModelRateLimitedError or 5 more`

      An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

      - `beta_managed_agents_unknown_error: object { message, retry_status, type }`

        An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `type: "retrying"`

              - `"retrying"`

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `type: "exhausted"`

              - `"exhausted"`

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

            - `type: "terminal"`

              - `"terminal"`

        - `type: "unknown_error"`

          - `"unknown_error"`

      - `beta_managed_agents_model_overloaded_error: object { message, retry_status, type }`

        The model is currently overloaded. Emitted after automatic retries are exhausted.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "model_overloaded_error"`

          - `"model_overloaded_error"`

      - `beta_managed_agents_model_rate_limited_error: object { message, retry_status, type }`

        The model request was rate-limited.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "model_rate_limited_error"`

          - `"model_rate_limited_error"`

      - `beta_managed_agents_model_request_failed_error: object { message, retry_status, type }`

        A model request failed for a reason other than overload or rate-limiting.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "model_request_failed_error"`

          - `"model_request_failed_error"`

      - `beta_managed_agents_mcp_connection_failed_error: object { mcp_server_name, message, retry_status, type }`

        Failed to connect to an MCP server.

        - `mcp_server_name: string`

          Name of the MCP server that failed to connect.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "mcp_connection_failed_error"`

          - `"mcp_connection_failed_error"`

      - `beta_managed_agents_mcp_authentication_failed_error: object { mcp_server_name, message, retry_status, type }`

        Authentication to an MCP server failed.

        - `mcp_server_name: string`

          Name of the MCP server that failed authentication.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "mcp_authentication_failed_error"`

          - `"mcp_authentication_failed_error"`

      - `beta_managed_agents_billing_error: object { message, retry_status, type }`

        The caller's organization or workspace cannot make model requests — out of credits or spend limit reached. Retrying with the same credentials will not succeed; the caller must resolve the billing state.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "billing_error"`

          - `"billing_error"`

      - `beta_managed_agents_credential_host_unreachable_error: object { credential_id, message, retry_status, 2 more }`

        An `environment_variable` credential's `auth.networking.allowed_hosts` includes a host the environment's network policy does not permit.

        - `credential_id: string`

          ID of the affected credential.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "credential_host_unreachable_error"`

          - `"credential_host_unreachable_error"`

        - `vault_id: string`

          ID of the vault containing the affected credential.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.error"`

      - `"session.error"`

  - `beta_managed_agents_session_status_rescheduled_event: object { id, processed_at, type }`

    Indicates the session is recovering from an error state and is rescheduled for execution.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.status_rescheduled"`

      - `"session.status_rescheduled"`

  - `beta_managed_agents_session_status_running_event: object { id, processed_at, type }`

    Indicates the session is actively running and the agent is working.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.status_running"`

      - `"session.status_running"`

  - `beta_managed_agents_session_status_idle_event: object { id, processed_at, stop_reason, type }`

    Indicates the agent has paused and is awaiting user input.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `stop_reason: BetaManagedAgentsSessionEndTurn or BetaManagedAgentsSessionRequiresAction or BetaManagedAgentsSessionRetriesExhausted`

      The agent completed its turn naturally and is ready for the next user message.

      - `beta_managed_agents_session_end_turn: object { type }`

        The agent completed its turn naturally and is ready for the next user message.

        - `type: "end_turn"`

          - `"end_turn"`

      - `beta_managed_agents_session_requires_action: object { event_ids, type }`

        The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

        - `event_ids: array of string`

          The ids of events the agent is blocked on. Resolving fewer than all re-emits `session.status_idle` with the remainder.

        - `type: "requires_action"`

          - `"requires_action"`

      - `beta_managed_agents_session_retries_exhausted: object { type }`

        The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

        - `type: "retries_exhausted"`

          - `"retries_exhausted"`

    - `type: "session.status_idle"`

      - `"session.status_idle"`

  - `beta_managed_agents_session_status_terminated_event: object { id, processed_at, type }`

    Indicates the session has terminated, either due to an error or completion.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.status_terminated"`

      - `"session.status_terminated"`

  - `beta_managed_agents_session_thread_created_event: object { id, agent_name, processed_at, 2 more }`

    Emitted when a subagent is spawned as a new thread. Written to the parent thread's output stream so clients observing the session see child creation.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the callable agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public `sthr_` ID of the newly created thread.

    - `type: "session.thread_created"`

      - `"session.thread_created"`

  - `beta_managed_agents_span_outcome_evaluation_start_event: object { id, iteration, outcome_id, 2 more }`

    Emitted when an outcome evaluation cycle begins.

    - `id: string`

      Unique identifier for this event.

    - `iteration: number`

      0-indexed revision cycle. 0 is the first evaluation; 1 is the re-evaluation after the first revision; etc.

    - `outcome_id: string`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.outcome_evaluation_start"`

      - `"span.outcome_evaluation_start"`

  - `beta_managed_agents_span_outcome_evaluation_end_event: object { id, explanation, iteration, 6 more }`

    Emitted when an outcome evaluation cycle completes. Carries the verdict and aggregate token usage. A verdict of `needs_revision` means another evaluation cycle follows; `satisfied`, `max_iterations_reached`, `failed`, or `interrupted` are terminal — no further evaluation cycles follow.

    - `id: string`

      Unique identifier for this event.

    - `explanation: string`

      Human-readable explanation of the verdict. For `needs_revision`, describes which criteria failed and why.

    - `iteration: number`

      0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

    - `outcome_evaluation_start_id: string`

      The id of the corresponding `span.outcome_evaluation_start` event.

    - `outcome_id: string`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `result: string`

      Evaluation verdict. 'satisfied': criteria met, session goes idle. 'needs_revision': criteria not met, another revision cycle follows. 'max_iterations_reached': evaluation budget exhausted with criteria still unmet — one final acknowledgment turn follows before the session goes idle, but no further evaluation runs. 'failed': grader determined the rubric does not apply to the deliverables. 'interrupted': user sent an interrupt while evaluation was in progress.

    - `type: "span.outcome_evaluation_end"`

      - `"span.outcome_evaluation_end"`

    - `usage: object { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }`

      Token usage for a single model request.

      - `cache_creation_input_tokens: number`

        Tokens used to create prompt cache in this request.

      - `cache_read_input_tokens: number`

        Tokens read from prompt cache in this request.

      - `input_tokens: number`

        Input tokens consumed by this request.

      - `output_tokens: number`

        Output tokens generated by this request.

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `"standard"`

        - `"fast"`

  - `beta_managed_agents_span_model_request_start_event: object { id, processed_at, type }`

    Emitted when a model request is initiated by the agent.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.model_request_start"`

      - `"span.model_request_start"`

  - `beta_managed_agents_span_model_request_end_event: object { id, is_error, model_request_start_id, 3 more }`

    Emitted when a model request completes.

    - `id: string`

      Unique identifier for this event.

    - `is_error: boolean`

      Whether the model request resulted in an error.

    - `model_request_start_id: string`

      The id of the corresponding `span.model_request_start` event.

    - `model_usage: object { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }`

      Token usage for a single model request.

      - `cache_creation_input_tokens: number`

        Tokens used to create prompt cache in this request.

      - `cache_read_input_tokens: number`

        Tokens read from prompt cache in this request.

      - `input_tokens: number`

        Input tokens consumed by this request.

      - `output_tokens: number`

        Output tokens generated by this request.

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.model_request_end"`

      - `"span.model_request_end"`

  - `beta_managed_agents_span_outcome_evaluation_ongoing_event: object { id, iteration, outcome_id, 2 more }`

    Periodic heartbeat emitted while an outcome evaluation cycle is in progress. Distinguishes 'evaluation is actively running' from 'evaluation is stuck' between the corresponding `span.outcome_evaluation_start` and `span.outcome_evaluation_end` events.

    - `id: string`

      Unique identifier for this event.

    - `iteration: number`

      0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

    - `outcome_id: string`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.outcome_evaluation_ongoing"`

      - `"span.outcome_evaluation_ongoing"`

  - `beta_managed_agents_user_define_outcome_event: object { id, description, max_iterations, 4 more }`

    Echo of a `user.define_outcome` input event. Carries the server-generated `outcome_id` that subsequent `span.outcome_evaluation_*` events reference.

    - `id: string`

      Unique identifier for this event.

    - `description: string`

      What the agent should produce. Copied from the input event.

    - `max_iterations: number`

      Evaluate-then-revise cycles before giving up. Default 3, max 20.

    - `outcome_id: string`

      Server-generated `outc_` ID for this outcome. Referenced by `span.outcome_evaluation_*` events and the session's `outcome_evaluations` list.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `rubric: BetaManagedAgentsFileRubric or BetaManagedAgentsTextRubric`

      Rubric for grading the quality of an outcome.

      - `beta_managed_agents_file_rubric: object { file_id, type }`

        Rubric referenced by a file uploaded via the Files API.

        - `file_id: string`

          ID of the rubric file.

        - `type: "file"`

          - `"file"`

      - `beta_managed_agents_text_rubric: object { content, type }`

        Rubric content provided inline as text.

        - `content: string`

          Rubric content. Plain text or markdown — the grader treats it as freeform text.

        - `type: "text"`

          - `"text"`

    - `type: "user.define_outcome"`

      - `"user.define_outcome"`

  - `beta_managed_agents_session_deleted_event: object { id, processed_at, type }`

    Emitted when a session has been deleted. Terminates any active event stream — no further events will be emitted for this session.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.deleted"`

      - `"session.deleted"`

  - `beta_managed_agents_session_thread_status_running_event: object { id, agent_name, processed_at, 2 more }`

    A session thread has begun executing. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that started running.

    - `type: "session.thread_status_running"`

      - `"session.thread_status_running"`

  - `beta_managed_agents_session_thread_status_idle_event: object { id, agent_name, processed_at, 3 more }`

    A session thread has yielded and is awaiting input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that went idle.

    - `stop_reason: BetaManagedAgentsSessionEndTurn or BetaManagedAgentsSessionRequiresAction or BetaManagedAgentsSessionRetriesExhausted`

      The agent completed its turn naturally and is ready for the next user message.

      - `beta_managed_agents_session_end_turn: object { type }`

        The agent completed its turn naturally and is ready for the next user message.

      - `beta_managed_agents_session_requires_action: object { event_ids, type }`

        The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

      - `beta_managed_agents_session_retries_exhausted: object { type }`

        The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

    - `type: "session.thread_status_idle"`

      - `"session.thread_status_idle"`

  - `beta_managed_agents_session_thread_status_terminated_event: object { id, agent_name, processed_at, 2 more }`

    A session thread has terminated and will accept no further input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that terminated.

    - `type: "session.thread_status_terminated"`

      - `"session.thread_status_terminated"`

  - `beta_managed_agents_user_tool_result_event: object { id, tool_use_id, type, 4 more }`

    Event sent by the client providing the result of an agent-toolset tool execution. Only valid on `self_hosted` environments, where sandbox-routed tools are executed by the client rather than the server.

    - `id: string`

      Unique identifier for this event.

    - `tool_use_id: string`

      The id of the `agent.tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: "user.tool_result"`

      - `"user.tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      Routes this result to a subagent thread. Copy from the `agent.tool_use` event's `session_thread_id`.

  - `beta_managed_agents_session_thread_status_rescheduled_event: object { id, agent_name, processed_at, 2 more }`

    A session thread hit a transient error and is retrying automatically. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that is retrying.

    - `type: "session.thread_status_rescheduled"`

      - `"session.thread_status_rescheduled"`

  - `beta_managed_agents_session_updated_event: object { id, processed_at, type, 3 more }`

    Emitted when an UpdateSession request changed at least one field. Carries only the fields that changed; absent fields were not part of the update. The new configuration applies from the next turn.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.updated"`

      - `"session.updated"`

    - `agent: optional object { id, description, mcp_servers, 8 more }`

      Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time.

      - `id: string`

      - `description: string`

      - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

        - `name: string`

        - `type: "url"`

          - `"url"`

        - `url: string`

      - `model: object { id, speed }`

        Model identifier and configuration.

        - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

          The model that will power your agent.

          See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

          - `"claude-fable-5"`

            Next generation of intelligence for the hardest knowledge work and coding problems

          - `"claude-opus-4-8"`

            Frontier intelligence for long-running agents and coding

          - `"claude-opus-4-7"`

            Frontier intelligence for long-running agents and coding

          - `"claude-opus-4-6"`

            Most intelligent model for building agents and coding

          - `"claude-sonnet-4-6"`

            Best combination of speed and intelligence

          - `"claude-haiku-4-5"`

            Fastest model with near-frontier intelligence

          - `"claude-haiku-4-5-20251001"`

            Fastest model with near-frontier intelligence

          - `"claude-opus-4-5"`

            Premium model combining maximum intelligence with practical performance

          - `"claude-opus-4-5-20251101"`

            Premium model combining maximum intelligence with practical performance

          - `"claude-sonnet-4-5"`

            High-performance model for agents and coding

          - `"claude-sonnet-4-5-20250929"`

            High-performance model for agents and coding

        - `speed: optional "standard" or "fast"`

          Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

          - `"standard"`

          - `"fast"`

      - `multiagent: object { agents, type }`

        Resolved coordinator topology with full agent definitions for each roster member.

        - `agents: array of BetaManagedAgentsSessionThreadAgent`

          Full `agent` definitions the coordinator may spawn as session threads.

          - `id: string`

          - `description: string`

          - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

            - `name: string`

            - `type: "url"`

            - `url: string`

          - `model: object { id, speed }`

            Model identifier and configuration.

            - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

              The model that will power your agent.

              See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

            - `speed: optional "standard" or "fast"`

              Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

          - `name: string`

          - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

            - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

              A resolved Anthropic-managed skill.

              - `skill_id: string`

              - `type: "anthropic"`

                - `"anthropic"`

              - `version: string`

            - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

              A resolved user-created custom skill.

              - `skill_id: string`

              - `type: "custom"`

                - `"custom"`

              - `version: string`

          - `system: string`

          - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

            - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

              - `configs: array of BetaManagedAgentsAgentToolConfig`

                - `enabled: boolean`

                - `name: "bash" or "edit" or "read" or 5 more`

                  Built-in agent tool identifier.

                  - `"bash"`

                  - `"edit"`

                  - `"read"`

                  - `"write"`

                  - `"glob"`

                  - `"grep"`

                  - `"web_fetch"`

                  - `"web_search"`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                    - `type: "always_allow"`

                      - `"always_allow"`

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

                    - `type: "always_ask"`

                      - `"always_ask"`

              - `default_config: object { enabled, permission_policy }`

                Resolved default configuration for agent tools.

                - `enabled: boolean`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

              - `type: "agent_toolset_20260401"`

                - `"agent_toolset_20260401"`

            - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

              - `configs: array of BetaManagedAgentsMCPToolConfig`

                - `enabled: boolean`

                - `name: string`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

              - `default_config: object { enabled, permission_policy }`

                Resolved default configuration for all tools from an MCP server.

                - `enabled: boolean`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

              - `mcp_server_name: string`

              - `type: "mcp_toolset"`

                - `"mcp_toolset"`

            - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

              A custom tool as returned in API responses.

              - `description: string`

              - `input_schema: object { type, properties, required }`

                JSON Schema for custom tool input parameters.

                - `type: "object"`

                - `properties: optional map[unknown]`

                - `required: optional array of string`

              - `name: string`

              - `type: "custom"`

                - `"custom"`

          - `type: "agent"`

            - `"agent"`

          - `version: number`

        - `type: "coordinator"`

          - `"coordinator"`

      - `name: string`

      - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

        - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

          A resolved Anthropic-managed skill.

        - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

          A resolved user-created custom skill.

      - `system: string`

      - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

        - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

        - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

        - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

          A custom tool as returned in API responses.

      - `type: "agent"`

        - `"agent"`

      - `version: number`

    - `metadata: optional map[string]`

      The session's full metadata bag after the update. Present when the update set non-empty metadata; absent when metadata was unchanged or cleared to empty.

    - `title: optional string`

      The session's new title. Present only when the update changed it.

  - `beta_managed_agents_system_message_event: object { id, content, type, processed_at }`

    A mid-conversation system message event. Carries system-role content that is appended to the session as a `role: "system"` turn.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsSystemContentBlock`

      System content blocks. Text-only.

      - `text: string`

        The text content.

      - `type: "text"`

        - `"text"`

    - `type: "system.message"`

      - `"system.message"`

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

### Beta Managed Agents System Message Event Params

- `beta_managed_agents_system_message_event_params: object { content, type }`

  Privileged context for the accompanying turn and all subsequent turns, appended to the session's system context as a `role: "system"` turn rather than replacing the top-level system prompt. At most one per request: it must be the final event and immediately follow the `user.message`, `user.tool_result`, or `user.custom_tool_result` it accompanies. Only supported on models that accept mid-conversation system messages.

  - `content: array of BetaManagedAgentsSystemContentBlock`

    System content blocks to append. Text-only.

    - `text: string`

      The text content.

    - `type: "text"`

      - `"text"`

  - `type: "system.message"`

    - `"system.message"`

### Beta Managed Agents Text Block

- `beta_managed_agents_text_block: object { text, type }`

  Regular text content.

  - `text: string`

    The text content.

  - `type: "text"`

    - `"text"`

### Beta Managed Agents Text Rubric

- `beta_managed_agents_text_rubric: object { content, type }`

  Rubric content provided inline as text.

  - `content: string`

    Rubric content. Plain text or markdown — the grader treats it as freeform text.

  - `type: "text"`

    - `"text"`

### Beta Managed Agents Text Rubric Params

- `beta_managed_agents_text_rubric_params: object { content, type }`

  Rubric content provided inline as text.

  - `content: string`

    Rubric content. Plain text or markdown — the grader treats it as freeform text. Maximum 262144 characters.

  - `type: "text"`

    - `"text"`

### Beta Managed Agents Unknown Error

- `beta_managed_agents_unknown_error: object { message, retry_status, type }`

  An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

  - `message: string`

    Human-readable error description.

  - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

    What the client should do next in response to this error.

    - `beta_managed_agents_retry_status_retrying: object { type }`

      The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

      - `type: "retrying"`

        - `"retrying"`

    - `beta_managed_agents_retry_status_exhausted: object { type }`

      This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

      - `type: "exhausted"`

        - `"exhausted"`

    - `beta_managed_agents_retry_status_terminal: object { type }`

      The session encountered a terminal error and will transition to `terminated` state.

      - `type: "terminal"`

        - `"terminal"`

  - `type: "unknown_error"`

    - `"unknown_error"`

### Beta Managed Agents URL Document Source

- `beta_managed_agents_url_document_source: object { type, url }`

  Document referenced by URL.

  - `type: "url"`

    - `"url"`

  - `url: string`

    URL of the document to fetch.

### Beta Managed Agents URL Image Source

- `beta_managed_agents_url_image_source: object { type, url }`

  Image referenced by URL.

  - `type: "url"`

    - `"url"`

  - `url: string`

    URL of the image to fetch.

### Beta Managed Agents User Custom Tool Result Event

- `beta_managed_agents_user_custom_tool_result_event: object { id, custom_tool_use_id, type, 4 more }`

  Event sent by the client providing the result of a custom tool execution.

  - `id: string`

    Unique identifier for this event.

  - `custom_tool_use_id: string`

    The id of the `agent.custom_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

  - `type: "user.custom_tool_result"`

    - `"user.custom_tool_result"`

  - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

    The result content returned by the tool.

    - `beta_managed_agents_text_block: object { text, type }`

      Regular text content.

      - `text: string`

        The text content.

      - `type: "text"`

        - `"text"`

    - `beta_managed_agents_image_block: object { source, type }`

      Image content specified directly as base64 data or as a reference via a URL.

      - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

        Union type for image source variants.

        - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

          Base64-encoded image data.

          - `data: string`

            Base64-encoded image data.

          - `media_type: string`

            MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_url_image_source: object { type, url }`

          Image referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the image to fetch.

        - `beta_managed_agents_file_image_source: object { file_id, type }`

          Image referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "image"`

        - `"image"`

    - `beta_managed_agents_document_block: object { source, type, context, title }`

      Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

        Union type for document source variants.

        - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

          Base64-encoded document data.

          - `data: string`

            Base64-encoded document data.

          - `media_type: string`

            MIME type of the document (e.g., "application/pdf").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

          Plain text document content.

          - `data: string`

            The plain text content.

          - `media_type: "text/plain"`

            MIME type of the text content. Must be "text/plain".

            - `"text/plain"`

          - `type: "text"`

            - `"text"`

        - `beta_managed_agents_url_document_source: object { type, url }`

          Document referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the document to fetch.

        - `beta_managed_agents_file_document_source: object { file_id, type }`

          Document referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "document"`

        - `"document"`

      - `context: optional string`

        Additional context about the document for the model.

      - `title: optional string`

        The title of the document.

    - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

      A block containing a web search result.

      - `citations: object { enabled }`

        Citation settings for a search result.

        - `enabled: boolean`

          Whether citations are enabled for this search result.

      - `content: array of BetaManagedAgentsSearchResultContent`

        Array of text content blocks from the search result.

        - `text: string`

          The text content.

        - `type: "text"`

          - `"text"`

      - `source: string`

        The URL source of the search result.

      - `title: string`

        The title of the search result.

      - `type: "search_result"`

        - `"search_result"`

  - `is_error: optional boolean`

    Whether the tool execution resulted in an error.

  - `processed_at: optional string`

    A timestamp in RFC 3339 format

  - `session_thread_id: optional string`

    Routes this result to a subagent thread. Copy from the `agent.custom_tool_use` event's `session_thread_id`.

### Beta Managed Agents User Custom Tool Result Event Params

- `beta_managed_agents_user_custom_tool_result_event_params: object { custom_tool_use_id, type, content, is_error }`

  Parameters for providing the result of a custom tool execution.

  - `custom_tool_use_id: string`

    The id of the `agent.custom_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

  - `type: "user.custom_tool_result"`

    - `"user.custom_tool_result"`

  - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

    The result content returned by the tool.

    - `beta_managed_agents_text_block: object { text, type }`

      Regular text content.

      - `text: string`

        The text content.

      - `type: "text"`

        - `"text"`

    - `beta_managed_agents_image_block: object { source, type }`

      Image content specified directly as base64 data or as a reference via a URL.

      - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

        Union type for image source variants.

        - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

          Base64-encoded image data.

          - `data: string`

            Base64-encoded image data.

          - `media_type: string`

            MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_url_image_source: object { type, url }`

          Image referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the image to fetch.

        - `beta_managed_agents_file_image_source: object { file_id, type }`

          Image referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "image"`

        - `"image"`

    - `beta_managed_agents_document_block: object { source, type, context, title }`

      Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

        Union type for document source variants.

        - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

          Base64-encoded document data.

          - `data: string`

            Base64-encoded document data.

          - `media_type: string`

            MIME type of the document (e.g., "application/pdf").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

          Plain text document content.

          - `data: string`

            The plain text content.

          - `media_type: "text/plain"`

            MIME type of the text content. Must be "text/plain".

            - `"text/plain"`

          - `type: "text"`

            - `"text"`

        - `beta_managed_agents_url_document_source: object { type, url }`

          Document referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the document to fetch.

        - `beta_managed_agents_file_document_source: object { file_id, type }`

          Document referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "document"`

        - `"document"`

      - `context: optional string`

        Additional context about the document for the model.

      - `title: optional string`

        The title of the document.

    - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

      A block containing a web search result.

      - `citations: object { enabled }`

        Citation settings for a search result.

        - `enabled: boolean`

          Whether citations are enabled for this search result.

      - `content: array of BetaManagedAgentsSearchResultContent`

        Array of text content blocks from the search result.

        - `text: string`

          The text content.

        - `type: "text"`

          - `"text"`

      - `source: string`

        The URL source of the search result.

      - `title: string`

        The title of the search result.

      - `type: "search_result"`

        - `"search_result"`

  - `is_error: optional boolean`

    Whether the tool execution resulted in an error.

### Beta Managed Agents User Define Outcome Event

- `beta_managed_agents_user_define_outcome_event: object { id, description, max_iterations, 4 more }`

  Echo of a `user.define_outcome` input event. Carries the server-generated `outcome_id` that subsequent `span.outcome_evaluation_*` events reference.

  - `id: string`

    Unique identifier for this event.

  - `description: string`

    What the agent should produce. Copied from the input event.

  - `max_iterations: number`

    Evaluate-then-revise cycles before giving up. Default 3, max 20.

  - `outcome_id: string`

    Server-generated `outc_` ID for this outcome. Referenced by `span.outcome_evaluation_*` events and the session's `outcome_evaluations` list.

  - `processed_at: string`

    A timestamp in RFC 3339 format

  - `rubric: BetaManagedAgentsFileRubric or BetaManagedAgentsTextRubric`

    Rubric for grading the quality of an outcome.

    - `beta_managed_agents_file_rubric: object { file_id, type }`

      Rubric referenced by a file uploaded via the Files API.

      - `file_id: string`

        ID of the rubric file.

      - `type: "file"`

        - `"file"`

    - `beta_managed_agents_text_rubric: object { content, type }`

      Rubric content provided inline as text.

      - `content: string`

        Rubric content. Plain text or markdown — the grader treats it as freeform text.

      - `type: "text"`

        - `"text"`

  - `type: "user.define_outcome"`

    - `"user.define_outcome"`

### Beta Managed Agents User Define Outcome Event Params

- `beta_managed_agents_user_define_outcome_event_params: object { description, rubric, type, max_iterations }`

  Parameters for defining an outcome the agent should work toward. The agent begins work on receipt.

  - `description: string`

    What the agent should produce. This is the task specification.

  - `rubric: BetaManagedAgentsFileRubricParams or BetaManagedAgentsTextRubricParams`

    Rubric for grading the quality of an outcome.

    - `beta_managed_agents_file_rubric_params: object { file_id, type }`

      Rubric referenced by a file uploaded via the Files API.

      - `file_id: string`

        ID of the rubric file.

      - `type: "file"`

        - `"file"`

    - `beta_managed_agents_text_rubric_params: object { content, type }`

      Rubric content provided inline as text.

      - `content: string`

        Rubric content. Plain text or markdown — the grader treats it as freeform text. Maximum 262144 characters.

      - `type: "text"`

        - `"text"`

  - `type: "user.define_outcome"`

    - `"user.define_outcome"`

  - `max_iterations: optional number`

    Eval→revision cycles before giving up. Default 3, max 20.

### Beta Managed Agents User Interrupt Event

- `beta_managed_agents_user_interrupt_event: object { id, type, processed_at, session_thread_id }`

  An interrupt event that pauses agent execution and returns control to the user.

  - `id: string`

    Unique identifier for this event.

  - `type: "user.interrupt"`

    - `"user.interrupt"`

  - `processed_at: optional string`

    A timestamp in RFC 3339 format

  - `session_thread_id: optional string`

    If absent, interrupts every non-archived thread in a multiagent session (or the primary alone in a single-agent session). If present, interrupts only the named thread.

### Beta Managed Agents User Interrupt Event Params

- `beta_managed_agents_user_interrupt_event_params: object { type, session_thread_id }`

  Parameters for sending an interrupt to pause the agent.

  - `type: "user.interrupt"`

    - `"user.interrupt"`

  - `session_thread_id: optional string`

    If absent, interrupts every non-archived thread in a multiagent session (or the primary alone in a single-agent session). If present, interrupts only the named thread.

### Beta Managed Agents User Message Event

- `beta_managed_agents_user_message_event: object { id, content, type, processed_at }`

  A user message event in the session conversation.

  - `id: string`

    Unique identifier for this event.

  - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

    Array of content blocks comprising the user message.

    - `beta_managed_agents_text_block: object { text, type }`

      Regular text content.

      - `text: string`

        The text content.

      - `type: "text"`

        - `"text"`

    - `beta_managed_agents_image_block: object { source, type }`

      Image content specified directly as base64 data or as a reference via a URL.

      - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

        Union type for image source variants.

        - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

          Base64-encoded image data.

          - `data: string`

            Base64-encoded image data.

          - `media_type: string`

            MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_url_image_source: object { type, url }`

          Image referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the image to fetch.

        - `beta_managed_agents_file_image_source: object { file_id, type }`

          Image referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "image"`

        - `"image"`

    - `beta_managed_agents_document_block: object { source, type, context, title }`

      Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

        Union type for document source variants.

        - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

          Base64-encoded document data.

          - `data: string`

            Base64-encoded document data.

          - `media_type: string`

            MIME type of the document (e.g., "application/pdf").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

          Plain text document content.

          - `data: string`

            The plain text content.

          - `media_type: "text/plain"`

            MIME type of the text content. Must be "text/plain".

            - `"text/plain"`

          - `type: "text"`

            - `"text"`

        - `beta_managed_agents_url_document_source: object { type, url }`

          Document referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the document to fetch.

        - `beta_managed_agents_file_document_source: object { file_id, type }`

          Document referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "document"`

        - `"document"`

      - `context: optional string`

        Additional context about the document for the model.

      - `title: optional string`

        The title of the document.

  - `type: "user.message"`

    - `"user.message"`

  - `processed_at: optional string`

    A timestamp in RFC 3339 format

### Beta Managed Agents User Message Event Params

- `beta_managed_agents_user_message_event_params: object { content, type }`

  Parameters for sending a user message to the session.

  - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

    Array of content blocks for the user message.

    - `beta_managed_agents_text_block: object { text, type }`

      Regular text content.

      - `text: string`

        The text content.

      - `type: "text"`

        - `"text"`

    - `beta_managed_agents_image_block: object { source, type }`

      Image content specified directly as base64 data or as a reference via a URL.

      - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

        Union type for image source variants.

        - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

          Base64-encoded image data.

          - `data: string`

            Base64-encoded image data.

          - `media_type: string`

            MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_url_image_source: object { type, url }`

          Image referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the image to fetch.

        - `beta_managed_agents_file_image_source: object { file_id, type }`

          Image referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "image"`

        - `"image"`

    - `beta_managed_agents_document_block: object { source, type, context, title }`

      Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

        Union type for document source variants.

        - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

          Base64-encoded document data.

          - `data: string`

            Base64-encoded document data.

          - `media_type: string`

            MIME type of the document (e.g., "application/pdf").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

          Plain text document content.

          - `data: string`

            The plain text content.

          - `media_type: "text/plain"`

            MIME type of the text content. Must be "text/plain".

            - `"text/plain"`

          - `type: "text"`

            - `"text"`

        - `beta_managed_agents_url_document_source: object { type, url }`

          Document referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the document to fetch.

        - `beta_managed_agents_file_document_source: object { file_id, type }`

          Document referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "document"`

        - `"document"`

      - `context: optional string`

        Additional context about the document for the model.

      - `title: optional string`

        The title of the document.

  - `type: "user.message"`

    - `"user.message"`

### Beta Managed Agents User Tool Confirmation Event

- `beta_managed_agents_user_tool_confirmation_event: object { id, result, tool_use_id, 4 more }`

  A tool confirmation event that approves or denies a pending tool execution.

  - `id: string`

    Unique identifier for this event.

  - `result: "allow" or "deny"`

    UserToolConfirmationResult enum

    - `"allow"`

    - `"deny"`

  - `tool_use_id: string`

    The id of the `agent.tool_use` or `agent.mcp_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

  - `type: "user.tool_confirmation"`

    - `"user.tool_confirmation"`

  - `deny_message: optional string`

    Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'.

  - `processed_at: optional string`

    A timestamp in RFC 3339 format

  - `session_thread_id: optional string`

    When set, the confirmation routes to this subagent's thread rather than the primary. Echo this from the `session_thread_id` on the `agent.tool_use` or `agent.mcp_tool_use` event that prompted the approval.

### Beta Managed Agents User Tool Confirmation Event Params

- `beta_managed_agents_user_tool_confirmation_event_params: object { result, tool_use_id, type, deny_message }`

  Parameters for confirming or denying a tool execution request.

  - `result: "allow" or "deny"`

    UserToolConfirmationResult enum

    - `"allow"`

    - `"deny"`

  - `tool_use_id: string`

    The id of the `agent.tool_use` or `agent.mcp_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

  - `type: "user.tool_confirmation"`

    - `"user.tool_confirmation"`

  - `deny_message: optional string`

    Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'.

### Beta Managed Agents User Tool Result Event Params

- `beta_managed_agents_user_tool_result_event_params: object { tool_use_id, type, content, is_error }`

  Parameters for providing the result of an agent-toolset tool execution. Only valid on `self_hosted` environments, where sandbox-routed tools are executed by the client rather than the server.

  - `tool_use_id: string`

    The id of the `agent.tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

  - `type: "user.tool_result"`

    - `"user.tool_result"`

  - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

    The result content returned by the tool.

    - `beta_managed_agents_text_block: object { text, type }`

      Regular text content.

      - `text: string`

        The text content.

      - `type: "text"`

        - `"text"`

    - `beta_managed_agents_image_block: object { source, type }`

      Image content specified directly as base64 data or as a reference via a URL.

      - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

        Union type for image source variants.

        - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

          Base64-encoded image data.

          - `data: string`

            Base64-encoded image data.

          - `media_type: string`

            MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_url_image_source: object { type, url }`

          Image referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the image to fetch.

        - `beta_managed_agents_file_image_source: object { file_id, type }`

          Image referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "image"`

        - `"image"`

    - `beta_managed_agents_document_block: object { source, type, context, title }`

      Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

        Union type for document source variants.

        - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

          Base64-encoded document data.

          - `data: string`

            Base64-encoded document data.

          - `media_type: string`

            MIME type of the document (e.g., "application/pdf").

          - `type: "base64"`

            - `"base64"`

        - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

          Plain text document content.

          - `data: string`

            The plain text content.

          - `media_type: "text/plain"`

            MIME type of the text content. Must be "text/plain".

            - `"text/plain"`

          - `type: "text"`

            - `"text"`

        - `beta_managed_agents_url_document_source: object { type, url }`

          Document referenced by URL.

          - `type: "url"`

            - `"url"`

          - `url: string`

            URL of the document to fetch.

        - `beta_managed_agents_file_document_source: object { file_id, type }`

          Document referenced by file ID.

          - `file_id: string`

            ID of a previously uploaded file.

          - `type: "file"`

            - `"file"`

      - `type: "document"`

        - `"document"`

      - `context: optional string`

        Additional context about the document for the model.

      - `title: optional string`

        The title of the document.

    - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

      A block containing a web search result.

      - `citations: object { enabled }`

        Citation settings for a search result.

        - `enabled: boolean`

          Whether citations are enabled for this search result.

      - `content: array of BetaManagedAgentsSearchResultContent`

        Array of text content blocks from the search result.

        - `text: string`

          The text content.

        - `type: "text"`

          - `"text"`

      - `source: string`

        The URL source of the search result.

      - `title: string`

        The title of the search result.

      - `type: "search_result"`

        - `"search_result"`

  - `is_error: optional boolean`

    Whether the tool execution resulted in an error.

# Resources

## Add Session Resource

`$ ant beta:sessions:resources add`

**post** `/v1/sessions/{session_id}/resources`

Add Session Resource

### Parameters

- `--session-id: string`

  Path param: Path parameter session_id

- `--file-id: string`

  Body param: ID of a previously uploaded file.

- `--type: "file"`

  Body param

- `--mount-path: optional string`

  Body param: Mount path in the container. Defaults to `/mnt/session/uploads/<file_id>`.

- `--beta: optional array of AnthropicBeta`

  Header param: Optional header to specify the beta version(s) you want to use.

### Returns

- `beta_managed_agents_file_resource: object { id, created_at, file_id, 3 more }`

  - `id: string`

  - `created_at: string`

    A timestamp in RFC 3339 format

  - `file_id: string`

  - `mount_path: string`

  - `type: "file"`

    - `"file"`

  - `updated_at: string`

    A timestamp in RFC 3339 format

### Example

```cli
ant beta:sessions:resources add \
  --api-key my-anthropic-api-key \
  --session-id sesn_011CZkZAtmR3yMPDzynEDxu7 \
  --file-id file_011CNha8iCJcU1wXNR6q4V8w \
  --type file
```

#### Response

```json
{
  "id": "sesrsc_011CZkZBJq5dWxk9fVLNcPht",
  "created_at": "2026-03-15T10:00:00Z",
  "file_id": "file_011CNha8iCJcU1wXNR6q4V8w",
  "mount_path": "/uploads/receipt.pdf",
  "type": "file",
  "updated_at": "2026-03-15T10:00:00Z"
}
```

## List Session Resources

`$ ant beta:sessions:resources list`

**get** `/v1/sessions/{session_id}/resources`

List Session Resources

### Parameters

- `--session-id: string`

  Path param: Path parameter session_id

- `--limit: optional number`

  Query param: Maximum number of resources to return per page (max 1000). If omitted, returns all resources.

- `--page: optional string`

  Query param: Opaque cursor from a previous response's next_page field.

- `--beta: optional array of AnthropicBeta`

  Header param: Optional header to specify the beta version(s) you want to use.

### Returns

- `BetaManagedAgentsListSessionResources: object { data, next_page }`

  Paginated list of resources attached to a session.

  - `data: array of BetaManagedAgentsSessionResource`

    Resources for the session, ordered by `created_at`.

    - `beta_managed_agents_github_repository_resource: object { id, created_at, mount_path, 4 more }`

      - `id: string`

      - `created_at: string`

        A timestamp in RFC 3339 format

      - `mount_path: string`

      - `type: "github_repository"`

        - `"github_repository"`

      - `updated_at: string`

        A timestamp in RFC 3339 format

      - `url: string`

      - `checkout: optional BetaManagedAgentsBranchCheckout or BetaManagedAgentsCommitCheckout`

        - `beta_managed_agents_branch_checkout: object { name, type }`

          - `name: string`

            Branch name to check out.

          - `type: "branch"`

            - `"branch"`

        - `beta_managed_agents_commit_checkout: object { sha, type }`

          - `sha: string`

            Full commit SHA to check out.

          - `type: "commit"`

            - `"commit"`

    - `beta_managed_agents_file_resource: object { id, created_at, file_id, 3 more }`

      - `id: string`

      - `created_at: string`

        A timestamp in RFC 3339 format

      - `file_id: string`

      - `mount_path: string`

      - `type: "file"`

        - `"file"`

      - `updated_at: string`

        A timestamp in RFC 3339 format

    - `beta_managed_agents_memory_store_resource: object { memory_store_id, type, access, 4 more }`

      A memory store attached to an agent session.

      - `memory_store_id: string`

        The memory store ID (memstore_...). Must belong to the caller's organization and workspace.

      - `type: "memory_store"`

        - `"memory_store"`

      - `access: optional "read_write" or "read_only"`

        Access mode for an attached memory store.

        - `"read_write"`

        - `"read_only"`

      - `description: optional string`

        Description of the memory store, snapshotted at attach time. Rendered into the agent's system prompt. Empty string when the store has no description.

      - `instructions: optional string`

        Per-attachment guidance for the agent on how to use this store. Rendered into the memory section of the system prompt. Max 4096 chars.

      - `mount_path: optional string`

        Filesystem path where the store is mounted in the session container, e.g. /mnt/memory/user-preferences. Derived from the store's name. Output-only.

      - `name: optional string`

        Display name of the memory store, snapshotted at attach time. Later edits to the store's name do not propagate to this resource.

  - `next_page: optional string`

    Opaque cursor for the next page. Null when no more results.

### Example

```cli
ant beta:sessions:resources list \
  --api-key my-anthropic-api-key \
  --session-id sesn_011CZkZAtmR3yMPDzynEDxu7
```

#### Response

```json
{
  "data": [
    {
      "id": "sesrsc_011CZkZBJq5dWxk9fVLNcPht",
      "created_at": "2026-03-15T10:00:00Z",
      "file_id": "file_011CNha8iCJcU1wXNR6q4V8w",
      "mount_path": "/uploads/receipt.pdf",
      "type": "file",
      "updated_at": "2026-03-15T10:00:00Z"
    },
    {
      "id": "sesrsc_011CZkZCKr6eXyl0gWMOdQiu",
      "created_at": "2026-03-15T10:00:00Z",
      "mount_path": "/workspace/example-repo",
      "type": "github_repository",
      "updated_at": "2026-03-15T10:00:00Z",
      "url": "https://github.com/example-org/example-repo",
      "checkout": {
        "name": "main",
        "type": "branch"
      }
    }
  ],
  "next_page": "page_MjAyNS0wNS0xNFQwMDowMDowMFo="
}
```

## Get Session Resource

`$ ant beta:sessions:resources retrieve`

**get** `/v1/sessions/{session_id}/resources/{resource_id}`

Get Session Resource

### Parameters

- `--session-id: string`

  Path param: Path parameter session_id

- `--resource-id: string`

  Path param: Path parameter resource_id

- `--beta: optional array of AnthropicBeta`

  Header param: Optional header to specify the beta version(s) you want to use.

### Returns

- `BetaSessionResourceGetResponse: BetaManagedAgentsGitHubRepositoryResource or BetaManagedAgentsFileResource or BetaManagedAgentsMemoryStoreResource`

  The requested session resource.

  - `beta_managed_agents_github_repository_resource: object { id, created_at, mount_path, 4 more }`

    - `id: string`

    - `created_at: string`

      A timestamp in RFC 3339 format

    - `mount_path: string`

    - `type: "github_repository"`

      - `"github_repository"`

    - `updated_at: string`

      A timestamp in RFC 3339 format

    - `url: string`

    - `checkout: optional BetaManagedAgentsBranchCheckout or BetaManagedAgentsCommitCheckout`

      - `beta_managed_agents_branch_checkout: object { name, type }`

        - `name: string`

          Branch name to check out.

        - `type: "branch"`

          - `"branch"`

      - `beta_managed_agents_commit_checkout: object { sha, type }`

        - `sha: string`

          Full commit SHA to check out.

        - `type: "commit"`

          - `"commit"`

  - `beta_managed_agents_file_resource: object { id, created_at, file_id, 3 more }`

    - `id: string`

    - `created_at: string`

      A timestamp in RFC 3339 format

    - `file_id: string`

    - `mount_path: string`

    - `type: "file"`

      - `"file"`

    - `updated_at: string`

      A timestamp in RFC 3339 format

  - `beta_managed_agents_memory_store_resource: object { memory_store_id, type, access, 4 more }`

    A memory store attached to an agent session.

    - `memory_store_id: string`

      The memory store ID (memstore_...). Must belong to the caller's organization and workspace.

    - `type: "memory_store"`

      - `"memory_store"`

    - `access: optional "read_write" or "read_only"`

      Access mode for an attached memory store.

      - `"read_write"`

      - `"read_only"`

    - `description: optional string`

      Description of the memory store, snapshotted at attach time. Rendered into the agent's system prompt. Empty string when the store has no description.

    - `instructions: optional string`

      Per-attachment guidance for the agent on how to use this store. Rendered into the memory section of the system prompt. Max 4096 chars.

    - `mount_path: optional string`

      Filesystem path where the store is mounted in the session container, e.g. /mnt/memory/user-preferences. Derived from the store's name. Output-only.

    - `name: optional string`

      Display name of the memory store, snapshotted at attach time. Later edits to the store's name do not propagate to this resource.

### Example

```cli
ant beta:sessions:resources retrieve \
  --api-key my-anthropic-api-key \
  --session-id sesn_011CZkZAtmR3yMPDzynEDxu7 \
  --resource-id sesrsc_011CZkZBJq5dWxk9fVLNcPht
```

#### Response

```json
{
  "id": "sesrsc_011CZkZCKr6eXyl0gWMOdQiu",
  "created_at": "2026-03-15T10:00:00Z",
  "mount_path": "/workspace/example-repo",
  "type": "github_repository",
  "updated_at": "2026-03-15T10:00:00Z",
  "url": "https://github.com/example-org/example-repo",
  "checkout": {
    "name": "main",
    "type": "branch"
  }
}
```

## Update Session Resource

`$ ant beta:sessions:resources update`

**post** `/v1/sessions/{session_id}/resources/{resource_id}`

Update Session Resource

### Parameters

- `--session-id: string`

  Path param: Path parameter session_id

- `--resource-id: string`

  Path param: Path parameter resource_id

- `--authorization-token: string`

  Body param: New authorization token for the resource. Currently only `github_repository` resources support token rotation.

- `--beta: optional array of AnthropicBeta`

  Header param: Optional header to specify the beta version(s) you want to use.

### Returns

- `BetaSessionResourceUpdateResponse: BetaManagedAgentsGitHubRepositoryResource or BetaManagedAgentsFileResource or BetaManagedAgentsMemoryStoreResource`

  The updated session resource.

  - `beta_managed_agents_github_repository_resource: object { id, created_at, mount_path, 4 more }`

    - `id: string`

    - `created_at: string`

      A timestamp in RFC 3339 format

    - `mount_path: string`

    - `type: "github_repository"`

      - `"github_repository"`

    - `updated_at: string`

      A timestamp in RFC 3339 format

    - `url: string`

    - `checkout: optional BetaManagedAgentsBranchCheckout or BetaManagedAgentsCommitCheckout`

      - `beta_managed_agents_branch_checkout: object { name, type }`

        - `name: string`

          Branch name to check out.

        - `type: "branch"`

          - `"branch"`

      - `beta_managed_agents_commit_checkout: object { sha, type }`

        - `sha: string`

          Full commit SHA to check out.

        - `type: "commit"`

          - `"commit"`

  - `beta_managed_agents_file_resource: object { id, created_at, file_id, 3 more }`

    - `id: string`

    - `created_at: string`

      A timestamp in RFC 3339 format

    - `file_id: string`

    - `mount_path: string`

    - `type: "file"`

      - `"file"`

    - `updated_at: string`

      A timestamp in RFC 3339 format

  - `beta_managed_agents_memory_store_resource: object { memory_store_id, type, access, 4 more }`

    A memory store attached to an agent session.

    - `memory_store_id: string`

      The memory store ID (memstore_...). Must belong to the caller's organization and workspace.

    - `type: "memory_store"`

      - `"memory_store"`

    - `access: optional "read_write" or "read_only"`

      Access mode for an attached memory store.

      - `"read_write"`

      - `"read_only"`

    - `description: optional string`

      Description of the memory store, snapshotted at attach time. Rendered into the agent's system prompt. Empty string when the store has no description.

    - `instructions: optional string`

      Per-attachment guidance for the agent on how to use this store. Rendered into the memory section of the system prompt. Max 4096 chars.

    - `mount_path: optional string`

      Filesystem path where the store is mounted in the session container, e.g. /mnt/memory/user-preferences. Derived from the store's name. Output-only.

    - `name: optional string`

      Display name of the memory store, snapshotted at attach time. Later edits to the store's name do not propagate to this resource.

### Example

```cli
ant beta:sessions:resources update \
  --api-key my-anthropic-api-key \
  --session-id sesn_011CZkZAtmR3yMPDzynEDxu7 \
  --resource-id sesrsc_011CZkZBJq5dWxk9fVLNcPht \
  --authorization-token ghp_exampletoken
```

#### Response

```json
{
  "id": "sesrsc_011CZkZCKr6eXyl0gWMOdQiu",
  "created_at": "2026-03-15T10:00:00Z",
  "mount_path": "/workspace/example-repo",
  "type": "github_repository",
  "updated_at": "2026-03-15T10:00:00Z",
  "url": "https://github.com/example-org/example-repo",
  "checkout": {
    "name": "main",
    "type": "branch"
  }
}
```

## Delete Session Resource

`$ ant beta:sessions:resources delete`

**delete** `/v1/sessions/{session_id}/resources/{resource_id}`

Delete Session Resource

### Parameters

- `--session-id: string`

  Path param: Path parameter session_id

- `--resource-id: string`

  Path param: Path parameter resource_id

- `--beta: optional array of AnthropicBeta`

  Header param: Optional header to specify the beta version(s) you want to use.

### Returns

- `beta_managed_agents_delete_session_resource: object { id, type }`

  Confirmation of resource deletion.

  - `id: string`

  - `type: "session_resource_deleted"`

    - `"session_resource_deleted"`

### Example

```cli
ant beta:sessions:resources delete \
  --api-key my-anthropic-api-key \
  --session-id sesn_011CZkZAtmR3yMPDzynEDxu7 \
  --resource-id sesrsc_011CZkZBJq5dWxk9fVLNcPht
```

#### Response

```json
{
  "id": "sesrsc_011CZkZBJq5dWxk9fVLNcPht",
  "type": "session_resource_deleted"
}
```

## Domain Types

### Beta Managed Agents Delete Session Resource

- `beta_managed_agents_delete_session_resource: object { id, type }`

  Confirmation of resource deletion.

  - `id: string`

  - `type: "session_resource_deleted"`

    - `"session_resource_deleted"`

### Beta Managed Agents File Resource

- `beta_managed_agents_file_resource: object { id, created_at, file_id, 3 more }`

  - `id: string`

  - `created_at: string`

    A timestamp in RFC 3339 format

  - `file_id: string`

  - `mount_path: string`

  - `type: "file"`

    - `"file"`

  - `updated_at: string`

    A timestamp in RFC 3339 format

### Beta Managed Agents GitHub Repository Resource

- `beta_managed_agents_github_repository_resource: object { id, created_at, mount_path, 4 more }`

  - `id: string`

  - `created_at: string`

    A timestamp in RFC 3339 format

  - `mount_path: string`

  - `type: "github_repository"`

    - `"github_repository"`

  - `updated_at: string`

    A timestamp in RFC 3339 format

  - `url: string`

  - `checkout: optional BetaManagedAgentsBranchCheckout or BetaManagedAgentsCommitCheckout`

    - `beta_managed_agents_branch_checkout: object { name, type }`

      - `name: string`

        Branch name to check out.

      - `type: "branch"`

        - `"branch"`

    - `beta_managed_agents_commit_checkout: object { sha, type }`

      - `sha: string`

        Full commit SHA to check out.

      - `type: "commit"`

        - `"commit"`

### Beta Managed Agents Memory Store Resource

- `beta_managed_agents_memory_store_resource: object { memory_store_id, type, access, 4 more }`

  A memory store attached to an agent session.

  - `memory_store_id: string`

    The memory store ID (memstore_...). Must belong to the caller's organization and workspace.

  - `type: "memory_store"`

    - `"memory_store"`

  - `access: optional "read_write" or "read_only"`

    Access mode for an attached memory store.

    - `"read_write"`

    - `"read_only"`

  - `description: optional string`

    Description of the memory store, snapshotted at attach time. Rendered into the agent's system prompt. Empty string when the store has no description.

  - `instructions: optional string`

    Per-attachment guidance for the agent on how to use this store. Rendered into the memory section of the system prompt. Max 4096 chars.

  - `mount_path: optional string`

    Filesystem path where the store is mounted in the session container, e.g. /mnt/memory/user-preferences. Derived from the store's name. Output-only.

  - `name: optional string`

    Display name of the memory store, snapshotted at attach time. Later edits to the store's name do not propagate to this resource.

### Beta Managed Agents Session Resource

- `beta_managed_agents_session_resource: BetaManagedAgentsGitHubRepositoryResource or BetaManagedAgentsFileResource or BetaManagedAgentsMemoryStoreResource`

  A memory store attached to an agent session.

  - `beta_managed_agents_github_repository_resource: object { id, created_at, mount_path, 4 more }`

    - `id: string`

    - `created_at: string`

      A timestamp in RFC 3339 format

    - `mount_path: string`

    - `type: "github_repository"`

      - `"github_repository"`

    - `updated_at: string`

      A timestamp in RFC 3339 format

    - `url: string`

    - `checkout: optional BetaManagedAgentsBranchCheckout or BetaManagedAgentsCommitCheckout`

      - `beta_managed_agents_branch_checkout: object { name, type }`

        - `name: string`

          Branch name to check out.

        - `type: "branch"`

          - `"branch"`

      - `beta_managed_agents_commit_checkout: object { sha, type }`

        - `sha: string`

          Full commit SHA to check out.

        - `type: "commit"`

          - `"commit"`

  - `beta_managed_agents_file_resource: object { id, created_at, file_id, 3 more }`

    - `id: string`

    - `created_at: string`

      A timestamp in RFC 3339 format

    - `file_id: string`

    - `mount_path: string`

    - `type: "file"`

      - `"file"`

    - `updated_at: string`

      A timestamp in RFC 3339 format

  - `beta_managed_agents_memory_store_resource: object { memory_store_id, type, access, 4 more }`

    A memory store attached to an agent session.

    - `memory_store_id: string`

      The memory store ID (memstore_...). Must belong to the caller's organization and workspace.

    - `type: "memory_store"`

      - `"memory_store"`

    - `access: optional "read_write" or "read_only"`

      Access mode for an attached memory store.

      - `"read_write"`

      - `"read_only"`

    - `description: optional string`

      Description of the memory store, snapshotted at attach time. Rendered into the agent's system prompt. Empty string when the store has no description.

    - `instructions: optional string`

      Per-attachment guidance for the agent on how to use this store. Rendered into the memory section of the system prompt. Max 4096 chars.

    - `mount_path: optional string`

      Filesystem path where the store is mounted in the session container, e.g. /mnt/memory/user-preferences. Derived from the store's name. Output-only.

    - `name: optional string`

      Display name of the memory store, snapshotted at attach time. Later edits to the store's name do not propagate to this resource.

# Threads

## List Session Threads

`$ ant beta:sessions:threads list`

**get** `/v1/sessions/{session_id}/threads`

List Session Threads

### Parameters

- `--session-id: string`

  Path param: Path parameter session_id

- `--limit: optional number`

  Query param: Maximum results per page. Defaults to 1000.

- `--page: optional string`

  Query param: Opaque pagination cursor from a previous response's next_page. Forward-only.

- `--beta: optional array of AnthropicBeta`

  Header param: Optional header to specify the beta version(s) you want to use.

### Returns

- `BetaManagedAgentsListSessionThreads: object { data, next_page }`

  Paginated list of threads within a `session`.

  - `data: optional array of BetaManagedAgentsSessionThread`

    Threads in the session, primary first then children in spawn order.

    - `id: string`

      Unique identifier for this thread.

    - `agent: object { id, description, mcp_servers, 7 more }`

      Resolved `agent` definition for a single `session_thread`. Snapshot of the agent at thread creation time. The multiagent roster is not repeated here; read it from `Session.agent`.

      - `id: string`

      - `description: string`

      - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

        - `name: string`

        - `type: "url"`

          - `"url"`

        - `url: string`

      - `model: object { id, speed }`

        Model identifier and configuration.

        - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

          The model that will power your agent.

          See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

          - `"claude-fable-5"`

            Next generation of intelligence for the hardest knowledge work and coding problems

          - `"claude-opus-4-8"`

            Frontier intelligence for long-running agents and coding

          - `"claude-opus-4-7"`

            Frontier intelligence for long-running agents and coding

          - `"claude-opus-4-6"`

            Most intelligent model for building agents and coding

          - `"claude-sonnet-4-6"`

            Best combination of speed and intelligence

          - `"claude-haiku-4-5"`

            Fastest model with near-frontier intelligence

          - `"claude-haiku-4-5-20251001"`

            Fastest model with near-frontier intelligence

          - `"claude-opus-4-5"`

            Premium model combining maximum intelligence with practical performance

          - `"claude-opus-4-5-20251101"`

            Premium model combining maximum intelligence with practical performance

          - `"claude-sonnet-4-5"`

            High-performance model for agents and coding

          - `"claude-sonnet-4-5-20250929"`

            High-performance model for agents and coding

        - `speed: optional "standard" or "fast"`

          Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

          - `"standard"`

          - `"fast"`

      - `name: string`

      - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

        - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

          A resolved Anthropic-managed skill.

          - `skill_id: string`

          - `type: "anthropic"`

            - `"anthropic"`

          - `version: string`

        - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

          A resolved user-created custom skill.

          - `skill_id: string`

          - `type: "custom"`

            - `"custom"`

          - `version: string`

      - `system: string`

      - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

        - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

          - `configs: array of BetaManagedAgentsAgentToolConfig`

            - `enabled: boolean`

            - `name: "bash" or "edit" or "read" or 5 more`

              Built-in agent tool identifier.

              - `"bash"`

              - `"edit"`

              - `"read"`

              - `"write"`

              - `"glob"`

              - `"grep"`

              - `"web_fetch"`

              - `"web_search"`

            - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

              Permission policy for tool execution.

              - `beta_managed_agents_always_allow_policy: object { type }`

                Tool calls are automatically approved without user confirmation.

                - `type: "always_allow"`

                  - `"always_allow"`

              - `beta_managed_agents_always_ask_policy: object { type }`

                Tool calls require user confirmation before execution.

                - `type: "always_ask"`

                  - `"always_ask"`

          - `default_config: object { enabled, permission_policy }`

            Resolved default configuration for agent tools.

            - `enabled: boolean`

            - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

              Permission policy for tool execution.

              - `beta_managed_agents_always_allow_policy: object { type }`

                Tool calls are automatically approved without user confirmation.

              - `beta_managed_agents_always_ask_policy: object { type }`

                Tool calls require user confirmation before execution.

          - `type: "agent_toolset_20260401"`

            - `"agent_toolset_20260401"`

        - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

          - `configs: array of BetaManagedAgentsMCPToolConfig`

            - `enabled: boolean`

            - `name: string`

            - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

              Permission policy for tool execution.

              - `beta_managed_agents_always_allow_policy: object { type }`

                Tool calls are automatically approved without user confirmation.

              - `beta_managed_agents_always_ask_policy: object { type }`

                Tool calls require user confirmation before execution.

          - `default_config: object { enabled, permission_policy }`

            Resolved default configuration for all tools from an MCP server.

            - `enabled: boolean`

            - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

              Permission policy for tool execution.

              - `beta_managed_agents_always_allow_policy: object { type }`

                Tool calls are automatically approved without user confirmation.

              - `beta_managed_agents_always_ask_policy: object { type }`

                Tool calls require user confirmation before execution.

          - `mcp_server_name: string`

          - `type: "mcp_toolset"`

            - `"mcp_toolset"`

        - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

          A custom tool as returned in API responses.

          - `description: string`

          - `input_schema: object { type, properties, required }`

            JSON Schema for custom tool input parameters.

            - `type: "object"`

            - `properties: optional map[unknown]`

            - `required: optional array of string`

          - `name: string`

          - `type: "custom"`

            - `"custom"`

      - `type: "agent"`

        - `"agent"`

      - `version: number`

    - `archived_at: string`

      A timestamp in RFC 3339 format

    - `created_at: string`

      A timestamp in RFC 3339 format

    - `parent_thread_id: string`

      Parent thread that spawned this thread. Null for the primary thread.

    - `session_id: string`

      The session this thread belongs to.

    - `stats: object { active_seconds, duration_seconds, startup_seconds }`

      Timing statistics for a session thread.

      - `active_seconds: optional number`

        Cumulative time in seconds the thread spent actively running. Excludes idle time.

      - `duration_seconds: optional number`

        Elapsed time since thread creation in seconds. For archived threads, frozen at the final update.

      - `startup_seconds: optional number`

        Time in seconds for the thread to begin running. Zero for child threads, which start immediately.

    - `status: "running" or "idle" or "rescheduling" or "terminated"`

      SessionThreadStatus enum

      - `"running"`

      - `"idle"`

      - `"rescheduling"`

      - `"terminated"`

    - `type: "session_thread"`

      - `"session_thread"`

    - `updated_at: string`

      A timestamp in RFC 3339 format

    - `usage: object { cache_creation, cache_read_input_tokens, input_tokens, output_tokens }`

      Cumulative token usage for a session thread across all turns.

      - `cache_creation: optional object { ephemeral_1h_input_tokens, ephemeral_5m_input_tokens }`

        Prompt-cache creation token usage broken down by cache lifetime.

        - `ephemeral_1h_input_tokens: optional number`

          Tokens used to create 1-hour ephemeral cache entries.

        - `ephemeral_5m_input_tokens: optional number`

          Tokens used to create 5-minute ephemeral cache entries.

      - `cache_read_input_tokens: optional number`

        Total tokens read from prompt cache.

      - `input_tokens: optional number`

        Total input tokens consumed across all turns.

      - `output_tokens: optional number`

        Total output tokens generated across all turns.

  - `next_page: optional string`

    Opaque cursor for the next page. Null when no more results.

### Example

```cli
ant beta:sessions:threads list \
  --api-key my-anthropic-api-key \
  --session-id sesn_011CZkZAtmR3yMPDzynEDxu7
```

#### Response

```json
{
  "data": [
    {
      "id": "sthr_011CZkZVWa6oIjw0rgXZpnBt",
      "agent": {
        "id": "agent_011CZkYqphY8vELVzwCUpqiQ",
        "description": "A focused research subagent.",
        "mcp_servers": [
          {
            "name": "example-mcp",
            "type": "url",
            "url": "https://example-server.modelcontextprotocol.io/sse"
          }
        ],
        "model": {
          "id": "claude-sonnet-4-6",
          "speed": "standard"
        },
        "name": "Researcher",
        "skills": [
          {
            "skill_id": "xlsx",
            "type": "anthropic",
            "version": "1"
          }
        ],
        "system": "You are a research subagent that gathers and summarises sources for the coordinating agent.",
        "tools": [
          {
            "configs": [
              {
                "enabled": true,
                "name": "bash",
                "permission_policy": {
                  "type": "always_allow"
                }
              }
            ],
            "default_config": {
              "enabled": true,
              "permission_policy": {
                "type": "always_ask"
              }
            },
            "type": "agent_toolset_20260401"
          }
        ],
        "type": "agent",
        "version": 1
      },
      "archived_at": null,
      "created_at": "2026-03-15T10:00:00Z",
      "parent_thread_id": null,
      "session_id": "sesn_011CZkZAtmR3yMPDzynEDxu7",
      "stats": {
        "active_seconds": 0,
        "duration_seconds": 0,
        "startup_seconds": 0
      },
      "status": "idle",
      "type": "session_thread",
      "updated_at": "2026-03-15T10:00:00Z",
      "usage": {
        "cache_creation": {
          "ephemeral_1h_input_tokens": 0,
          "ephemeral_5m_input_tokens": 0
        },
        "cache_read_input_tokens": 0,
        "input_tokens": 0,
        "output_tokens": 0
      }
    }
  ],
  "next_page": "page_MjAyNS0wNS0xNFQwMDowMDowMFo="
}
```

## Get Session Thread

`$ ant beta:sessions:threads retrieve`

**get** `/v1/sessions/{session_id}/threads/{thread_id}`

Get Session Thread

### Parameters

- `--session-id: string`

  Path param: Path parameter session_id

- `--thread-id: string`

  Path param: Path parameter thread_id

- `--beta: optional array of AnthropicBeta`

  Header param: Optional header to specify the beta version(s) you want to use.

### Returns

- `beta_managed_agents_session_thread: object { id, agent, archived_at, 8 more }`

  An execution thread within a `session`. Each session has one primary thread plus zero or more child threads spawned by the coordinator.

  - `id: string`

    Unique identifier for this thread.

  - `agent: object { id, description, mcp_servers, 7 more }`

    Resolved `agent` definition for a single `session_thread`. Snapshot of the agent at thread creation time. The multiagent roster is not repeated here; read it from `Session.agent`.

    - `id: string`

    - `description: string`

    - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

      - `name: string`

      - `type: "url"`

        - `"url"`

      - `url: string`

    - `model: object { id, speed }`

      Model identifier and configuration.

      - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

        The model that will power your agent.

        See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

        - `"claude-fable-5"`

          Next generation of intelligence for the hardest knowledge work and coding problems

        - `"claude-opus-4-8"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-7"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-6"`

          Most intelligent model for building agents and coding

        - `"claude-sonnet-4-6"`

          Best combination of speed and intelligence

        - `"claude-haiku-4-5"`

          Fastest model with near-frontier intelligence

        - `"claude-haiku-4-5-20251001"`

          Fastest model with near-frontier intelligence

        - `"claude-opus-4-5"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-opus-4-5-20251101"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-sonnet-4-5"`

          High-performance model for agents and coding

        - `"claude-sonnet-4-5-20250929"`

          High-performance model for agents and coding

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `"standard"`

        - `"fast"`

    - `name: string`

    - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

      - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

        A resolved Anthropic-managed skill.

        - `skill_id: string`

        - `type: "anthropic"`

          - `"anthropic"`

        - `version: string`

      - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

        A resolved user-created custom skill.

        - `skill_id: string`

        - `type: "custom"`

          - `"custom"`

        - `version: string`

    - `system: string`

    - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

      - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

        - `configs: array of BetaManagedAgentsAgentToolConfig`

          - `enabled: boolean`

          - `name: "bash" or "edit" or "read" or 5 more`

            Built-in agent tool identifier.

            - `"bash"`

            - `"edit"`

            - `"read"`

            - `"write"`

            - `"glob"`

            - `"grep"`

            - `"web_fetch"`

            - `"web_search"`

          - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

            Permission policy for tool execution.

            - `beta_managed_agents_always_allow_policy: object { type }`

              Tool calls are automatically approved without user confirmation.

              - `type: "always_allow"`

                - `"always_allow"`

            - `beta_managed_agents_always_ask_policy: object { type }`

              Tool calls require user confirmation before execution.

              - `type: "always_ask"`

                - `"always_ask"`

        - `default_config: object { enabled, permission_policy }`

          Resolved default configuration for agent tools.

          - `enabled: boolean`

          - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

            Permission policy for tool execution.

            - `beta_managed_agents_always_allow_policy: object { type }`

              Tool calls are automatically approved without user confirmation.

            - `beta_managed_agents_always_ask_policy: object { type }`

              Tool calls require user confirmation before execution.

        - `type: "agent_toolset_20260401"`

          - `"agent_toolset_20260401"`

      - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

        - `configs: array of BetaManagedAgentsMCPToolConfig`

          - `enabled: boolean`

          - `name: string`

          - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

            Permission policy for tool execution.

            - `beta_managed_agents_always_allow_policy: object { type }`

              Tool calls are automatically approved without user confirmation.

            - `beta_managed_agents_always_ask_policy: object { type }`

              Tool calls require user confirmation before execution.

        - `default_config: object { enabled, permission_policy }`

          Resolved default configuration for all tools from an MCP server.

          - `enabled: boolean`

          - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

            Permission policy for tool execution.

            - `beta_managed_agents_always_allow_policy: object { type }`

              Tool calls are automatically approved without user confirmation.

            - `beta_managed_agents_always_ask_policy: object { type }`

              Tool calls require user confirmation before execution.

        - `mcp_server_name: string`

        - `type: "mcp_toolset"`

          - `"mcp_toolset"`

      - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

        A custom tool as returned in API responses.

        - `description: string`

        - `input_schema: object { type, properties, required }`

          JSON Schema for custom tool input parameters.

          - `type: "object"`

          - `properties: optional map[unknown]`

          - `required: optional array of string`

        - `name: string`

        - `type: "custom"`

          - `"custom"`

    - `type: "agent"`

      - `"agent"`

    - `version: number`

  - `archived_at: string`

    A timestamp in RFC 3339 format

  - `created_at: string`

    A timestamp in RFC 3339 format

  - `parent_thread_id: string`

    Parent thread that spawned this thread. Null for the primary thread.

  - `session_id: string`

    The session this thread belongs to.

  - `stats: object { active_seconds, duration_seconds, startup_seconds }`

    Timing statistics for a session thread.

    - `active_seconds: optional number`

      Cumulative time in seconds the thread spent actively running. Excludes idle time.

    - `duration_seconds: optional number`

      Elapsed time since thread creation in seconds. For archived threads, frozen at the final update.

    - `startup_seconds: optional number`

      Time in seconds for the thread to begin running. Zero for child threads, which start immediately.

  - `status: "running" or "idle" or "rescheduling" or "terminated"`

    SessionThreadStatus enum

    - `"running"`

    - `"idle"`

    - `"rescheduling"`

    - `"terminated"`

  - `type: "session_thread"`

    - `"session_thread"`

  - `updated_at: string`

    A timestamp in RFC 3339 format

  - `usage: object { cache_creation, cache_read_input_tokens, input_tokens, output_tokens }`

    Cumulative token usage for a session thread across all turns.

    - `cache_creation: optional object { ephemeral_1h_input_tokens, ephemeral_5m_input_tokens }`

      Prompt-cache creation token usage broken down by cache lifetime.

      - `ephemeral_1h_input_tokens: optional number`

        Tokens used to create 1-hour ephemeral cache entries.

      - `ephemeral_5m_input_tokens: optional number`

        Tokens used to create 5-minute ephemeral cache entries.

    - `cache_read_input_tokens: optional number`

      Total tokens read from prompt cache.

    - `input_tokens: optional number`

      Total input tokens consumed across all turns.

    - `output_tokens: optional number`

      Total output tokens generated across all turns.

### Example

```cli
ant beta:sessions:threads retrieve \
  --api-key my-anthropic-api-key \
  --session-id sesn_011CZkZAtmR3yMPDzynEDxu7 \
  --thread-id sthr_011CZkZVWa6oIjw0rgXZpnBt
```

#### Response

```json
{
  "id": "sthr_011CZkZVWa6oIjw0rgXZpnBt",
  "agent": {
    "id": "agent_011CZkYqphY8vELVzwCUpqiQ",
    "description": "A focused research subagent.",
    "mcp_servers": [
      {
        "name": "example-mcp",
        "type": "url",
        "url": "https://example-server.modelcontextprotocol.io/sse"
      }
    ],
    "model": {
      "id": "claude-sonnet-4-6",
      "speed": "standard"
    },
    "name": "Researcher",
    "skills": [
      {
        "skill_id": "xlsx",
        "type": "anthropic",
        "version": "1"
      }
    ],
    "system": "You are a research subagent that gathers and summarises sources for the coordinating agent.",
    "tools": [
      {
        "configs": [
          {
            "enabled": true,
            "name": "bash",
            "permission_policy": {
              "type": "always_allow"
            }
          }
        ],
        "default_config": {
          "enabled": true,
          "permission_policy": {
            "type": "always_ask"
          }
        },
        "type": "agent_toolset_20260401"
      }
    ],
    "type": "agent",
    "version": 1
  },
  "archived_at": null,
  "created_at": "2026-03-15T10:00:00Z",
  "parent_thread_id": null,
  "session_id": "sesn_011CZkZAtmR3yMPDzynEDxu7",
  "stats": {
    "active_seconds": 0,
    "duration_seconds": 0,
    "startup_seconds": 0
  },
  "status": "idle",
  "type": "session_thread",
  "updated_at": "2026-03-15T10:00:00Z",
  "usage": {
    "cache_creation": {
      "ephemeral_1h_input_tokens": 0,
      "ephemeral_5m_input_tokens": 0
    },
    "cache_read_input_tokens": 0,
    "input_tokens": 0,
    "output_tokens": 0
  }
}
```

## Archive Session Thread

`$ ant beta:sessions:threads archive`

**post** `/v1/sessions/{session_id}/threads/{thread_id}/archive`

Archive Session Thread

### Parameters

- `--session-id: string`

  Path param: Path parameter session_id

- `--thread-id: string`

  Path param: Path parameter thread_id

- `--beta: optional array of AnthropicBeta`

  Header param: Optional header to specify the beta version(s) you want to use.

### Returns

- `beta_managed_agents_session_thread: object { id, agent, archived_at, 8 more }`

  An execution thread within a `session`. Each session has one primary thread plus zero or more child threads spawned by the coordinator.

  - `id: string`

    Unique identifier for this thread.

  - `agent: object { id, description, mcp_servers, 7 more }`

    Resolved `agent` definition for a single `session_thread`. Snapshot of the agent at thread creation time. The multiagent roster is not repeated here; read it from `Session.agent`.

    - `id: string`

    - `description: string`

    - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

      - `name: string`

      - `type: "url"`

        - `"url"`

      - `url: string`

    - `model: object { id, speed }`

      Model identifier and configuration.

      - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

        The model that will power your agent.

        See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

        - `"claude-fable-5"`

          Next generation of intelligence for the hardest knowledge work and coding problems

        - `"claude-opus-4-8"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-7"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-6"`

          Most intelligent model for building agents and coding

        - `"claude-sonnet-4-6"`

          Best combination of speed and intelligence

        - `"claude-haiku-4-5"`

          Fastest model with near-frontier intelligence

        - `"claude-haiku-4-5-20251001"`

          Fastest model with near-frontier intelligence

        - `"claude-opus-4-5"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-opus-4-5-20251101"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-sonnet-4-5"`

          High-performance model for agents and coding

        - `"claude-sonnet-4-5-20250929"`

          High-performance model for agents and coding

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `"standard"`

        - `"fast"`

    - `name: string`

    - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

      - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

        A resolved Anthropic-managed skill.

        - `skill_id: string`

        - `type: "anthropic"`

          - `"anthropic"`

        - `version: string`

      - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

        A resolved user-created custom skill.

        - `skill_id: string`

        - `type: "custom"`

          - `"custom"`

        - `version: string`

    - `system: string`

    - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

      - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

        - `configs: array of BetaManagedAgentsAgentToolConfig`

          - `enabled: boolean`

          - `name: "bash" or "edit" or "read" or 5 more`

            Built-in agent tool identifier.

            - `"bash"`

            - `"edit"`

            - `"read"`

            - `"write"`

            - `"glob"`

            - `"grep"`

            - `"web_fetch"`

            - `"web_search"`

          - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

            Permission policy for tool execution.

            - `beta_managed_agents_always_allow_policy: object { type }`

              Tool calls are automatically approved without user confirmation.

              - `type: "always_allow"`

                - `"always_allow"`

            - `beta_managed_agents_always_ask_policy: object { type }`

              Tool calls require user confirmation before execution.

              - `type: "always_ask"`

                - `"always_ask"`

        - `default_config: object { enabled, permission_policy }`

          Resolved default configuration for agent tools.

          - `enabled: boolean`

          - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

            Permission policy for tool execution.

            - `beta_managed_agents_always_allow_policy: object { type }`

              Tool calls are automatically approved without user confirmation.

            - `beta_managed_agents_always_ask_policy: object { type }`

              Tool calls require user confirmation before execution.

        - `type: "agent_toolset_20260401"`

          - `"agent_toolset_20260401"`

      - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

        - `configs: array of BetaManagedAgentsMCPToolConfig`

          - `enabled: boolean`

          - `name: string`

          - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

            Permission policy for tool execution.

            - `beta_managed_agents_always_allow_policy: object { type }`

              Tool calls are automatically approved without user confirmation.

            - `beta_managed_agents_always_ask_policy: object { type }`

              Tool calls require user confirmation before execution.

        - `default_config: object { enabled, permission_policy }`

          Resolved default configuration for all tools from an MCP server.

          - `enabled: boolean`

          - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

            Permission policy for tool execution.

            - `beta_managed_agents_always_allow_policy: object { type }`

              Tool calls are automatically approved without user confirmation.

            - `beta_managed_agents_always_ask_policy: object { type }`

              Tool calls require user confirmation before execution.

        - `mcp_server_name: string`

        - `type: "mcp_toolset"`

          - `"mcp_toolset"`

      - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

        A custom tool as returned in API responses.

        - `description: string`

        - `input_schema: object { type, properties, required }`

          JSON Schema for custom tool input parameters.

          - `type: "object"`

          - `properties: optional map[unknown]`

          - `required: optional array of string`

        - `name: string`

        - `type: "custom"`

          - `"custom"`

    - `type: "agent"`

      - `"agent"`

    - `version: number`

  - `archived_at: string`

    A timestamp in RFC 3339 format

  - `created_at: string`

    A timestamp in RFC 3339 format

  - `parent_thread_id: string`

    Parent thread that spawned this thread. Null for the primary thread.

  - `session_id: string`

    The session this thread belongs to.

  - `stats: object { active_seconds, duration_seconds, startup_seconds }`

    Timing statistics for a session thread.

    - `active_seconds: optional number`

      Cumulative time in seconds the thread spent actively running. Excludes idle time.

    - `duration_seconds: optional number`

      Elapsed time since thread creation in seconds. For archived threads, frozen at the final update.

    - `startup_seconds: optional number`

      Time in seconds for the thread to begin running. Zero for child threads, which start immediately.

  - `status: "running" or "idle" or "rescheduling" or "terminated"`

    SessionThreadStatus enum

    - `"running"`

    - `"idle"`

    - `"rescheduling"`

    - `"terminated"`

  - `type: "session_thread"`

    - `"session_thread"`

  - `updated_at: string`

    A timestamp in RFC 3339 format

  - `usage: object { cache_creation, cache_read_input_tokens, input_tokens, output_tokens }`

    Cumulative token usage for a session thread across all turns.

    - `cache_creation: optional object { ephemeral_1h_input_tokens, ephemeral_5m_input_tokens }`

      Prompt-cache creation token usage broken down by cache lifetime.

      - `ephemeral_1h_input_tokens: optional number`

        Tokens used to create 1-hour ephemeral cache entries.

      - `ephemeral_5m_input_tokens: optional number`

        Tokens used to create 5-minute ephemeral cache entries.

    - `cache_read_input_tokens: optional number`

      Total tokens read from prompt cache.

    - `input_tokens: optional number`

      Total input tokens consumed across all turns.

    - `output_tokens: optional number`

      Total output tokens generated across all turns.

### Example

```cli
ant beta:sessions:threads archive \
  --api-key my-anthropic-api-key \
  --session-id sesn_011CZkZAtmR3yMPDzynEDxu7 \
  --thread-id sthr_011CZkZVWa6oIjw0rgXZpnBt
```

#### Response

```json
{
  "id": "sthr_011CZkZVWa6oIjw0rgXZpnBt",
  "agent": {
    "id": "agent_011CZkYqphY8vELVzwCUpqiQ",
    "description": "A focused research subagent.",
    "mcp_servers": [
      {
        "name": "example-mcp",
        "type": "url",
        "url": "https://example-server.modelcontextprotocol.io/sse"
      }
    ],
    "model": {
      "id": "claude-sonnet-4-6",
      "speed": "standard"
    },
    "name": "Researcher",
    "skills": [
      {
        "skill_id": "xlsx",
        "type": "anthropic",
        "version": "1"
      }
    ],
    "system": "You are a research subagent that gathers and summarises sources for the coordinating agent.",
    "tools": [
      {
        "configs": [
          {
            "enabled": true,
            "name": "bash",
            "permission_policy": {
              "type": "always_allow"
            }
          }
        ],
        "default_config": {
          "enabled": true,
          "permission_policy": {
            "type": "always_ask"
          }
        },
        "type": "agent_toolset_20260401"
      }
    ],
    "type": "agent",
    "version": 1
  },
  "archived_at": null,
  "created_at": "2026-03-15T10:00:00Z",
  "parent_thread_id": null,
  "session_id": "sesn_011CZkZAtmR3yMPDzynEDxu7",
  "stats": {
    "active_seconds": 0,
    "duration_seconds": 0,
    "startup_seconds": 0
  },
  "status": "idle",
  "type": "session_thread",
  "updated_at": "2026-03-15T10:00:00Z",
  "usage": {
    "cache_creation": {
      "ephemeral_1h_input_tokens": 0,
      "ephemeral_5m_input_tokens": 0
    },
    "cache_read_input_tokens": 0,
    "input_tokens": 0,
    "output_tokens": 0
  }
}
```

## Domain Types

### Beta Managed Agents Session Thread

- `beta_managed_agents_session_thread: object { id, agent, archived_at, 8 more }`

  An execution thread within a `session`. Each session has one primary thread plus zero or more child threads spawned by the coordinator.

  - `id: string`

    Unique identifier for this thread.

  - `agent: object { id, description, mcp_servers, 7 more }`

    Resolved `agent` definition for a single `session_thread`. Snapshot of the agent at thread creation time. The multiagent roster is not repeated here; read it from `Session.agent`.

    - `id: string`

    - `description: string`

    - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

      - `name: string`

      - `type: "url"`

        - `"url"`

      - `url: string`

    - `model: object { id, speed }`

      Model identifier and configuration.

      - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

        The model that will power your agent.

        See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

        - `"claude-fable-5"`

          Next generation of intelligence for the hardest knowledge work and coding problems

        - `"claude-opus-4-8"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-7"`

          Frontier intelligence for long-running agents and coding

        - `"claude-opus-4-6"`

          Most intelligent model for building agents and coding

        - `"claude-sonnet-4-6"`

          Best combination of speed and intelligence

        - `"claude-haiku-4-5"`

          Fastest model with near-frontier intelligence

        - `"claude-haiku-4-5-20251001"`

          Fastest model with near-frontier intelligence

        - `"claude-opus-4-5"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-opus-4-5-20251101"`

          Premium model combining maximum intelligence with practical performance

        - `"claude-sonnet-4-5"`

          High-performance model for agents and coding

        - `"claude-sonnet-4-5-20250929"`

          High-performance model for agents and coding

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `"standard"`

        - `"fast"`

    - `name: string`

    - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

      - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

        A resolved Anthropic-managed skill.

        - `skill_id: string`

        - `type: "anthropic"`

          - `"anthropic"`

        - `version: string`

      - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

        A resolved user-created custom skill.

        - `skill_id: string`

        - `type: "custom"`

          - `"custom"`

        - `version: string`

    - `system: string`

    - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

      - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

        - `configs: array of BetaManagedAgentsAgentToolConfig`

          - `enabled: boolean`

          - `name: "bash" or "edit" or "read" or 5 more`

            Built-in agent tool identifier.

            - `"bash"`

            - `"edit"`

            - `"read"`

            - `"write"`

            - `"glob"`

            - `"grep"`

            - `"web_fetch"`

            - `"web_search"`

          - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

            Permission policy for tool execution.

            - `beta_managed_agents_always_allow_policy: object { type }`

              Tool calls are automatically approved without user confirmation.

              - `type: "always_allow"`

                - `"always_allow"`

            - `beta_managed_agents_always_ask_policy: object { type }`

              Tool calls require user confirmation before execution.

              - `type: "always_ask"`

                - `"always_ask"`

        - `default_config: object { enabled, permission_policy }`

          Resolved default configuration for agent tools.

          - `enabled: boolean`

          - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

            Permission policy for tool execution.

            - `beta_managed_agents_always_allow_policy: object { type }`

              Tool calls are automatically approved without user confirmation.

            - `beta_managed_agents_always_ask_policy: object { type }`

              Tool calls require user confirmation before execution.

        - `type: "agent_toolset_20260401"`

          - `"agent_toolset_20260401"`

      - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

        - `configs: array of BetaManagedAgentsMCPToolConfig`

          - `enabled: boolean`

          - `name: string`

          - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

            Permission policy for tool execution.

            - `beta_managed_agents_always_allow_policy: object { type }`

              Tool calls are automatically approved without user confirmation.

            - `beta_managed_agents_always_ask_policy: object { type }`

              Tool calls require user confirmation before execution.

        - `default_config: object { enabled, permission_policy }`

          Resolved default configuration for all tools from an MCP server.

          - `enabled: boolean`

          - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

            Permission policy for tool execution.

            - `beta_managed_agents_always_allow_policy: object { type }`

              Tool calls are automatically approved without user confirmation.

            - `beta_managed_agents_always_ask_policy: object { type }`

              Tool calls require user confirmation before execution.

        - `mcp_server_name: string`

        - `type: "mcp_toolset"`

          - `"mcp_toolset"`

      - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

        A custom tool as returned in API responses.

        - `description: string`

        - `input_schema: object { type, properties, required }`

          JSON Schema for custom tool input parameters.

          - `type: "object"`

          - `properties: optional map[unknown]`

          - `required: optional array of string`

        - `name: string`

        - `type: "custom"`

          - `"custom"`

    - `type: "agent"`

      - `"agent"`

    - `version: number`

  - `archived_at: string`

    A timestamp in RFC 3339 format

  - `created_at: string`

    A timestamp in RFC 3339 format

  - `parent_thread_id: string`

    Parent thread that spawned this thread. Null for the primary thread.

  - `session_id: string`

    The session this thread belongs to.

  - `stats: object { active_seconds, duration_seconds, startup_seconds }`

    Timing statistics for a session thread.

    - `active_seconds: optional number`

      Cumulative time in seconds the thread spent actively running. Excludes idle time.

    - `duration_seconds: optional number`

      Elapsed time since thread creation in seconds. For archived threads, frozen at the final update.

    - `startup_seconds: optional number`

      Time in seconds for the thread to begin running. Zero for child threads, which start immediately.

  - `status: "running" or "idle" or "rescheduling" or "terminated"`

    SessionThreadStatus enum

    - `"running"`

    - `"idle"`

    - `"rescheduling"`

    - `"terminated"`

  - `type: "session_thread"`

    - `"session_thread"`

  - `updated_at: string`

    A timestamp in RFC 3339 format

  - `usage: object { cache_creation, cache_read_input_tokens, input_tokens, output_tokens }`

    Cumulative token usage for a session thread across all turns.

    - `cache_creation: optional object { ephemeral_1h_input_tokens, ephemeral_5m_input_tokens }`

      Prompt-cache creation token usage broken down by cache lifetime.

      - `ephemeral_1h_input_tokens: optional number`

        Tokens used to create 1-hour ephemeral cache entries.

      - `ephemeral_5m_input_tokens: optional number`

        Tokens used to create 5-minute ephemeral cache entries.

    - `cache_read_input_tokens: optional number`

      Total tokens read from prompt cache.

    - `input_tokens: optional number`

      Total input tokens consumed across all turns.

    - `output_tokens: optional number`

      Total output tokens generated across all turns.

### Beta Managed Agents Session Thread Stats

- `beta_managed_agents_session_thread_stats: object { active_seconds, duration_seconds, startup_seconds }`

  Timing statistics for a session thread.

  - `active_seconds: optional number`

    Cumulative time in seconds the thread spent actively running. Excludes idle time.

  - `duration_seconds: optional number`

    Elapsed time since thread creation in seconds. For archived threads, frozen at the final update.

  - `startup_seconds: optional number`

    Time in seconds for the thread to begin running. Zero for child threads, which start immediately.

### Beta Managed Agents Session Thread Status

- `beta_managed_agents_session_thread_status: "running" or "idle" or "rescheduling" or "terminated"`

  SessionThreadStatus enum

  - `"running"`

  - `"idle"`

  - `"rescheduling"`

  - `"terminated"`

### Beta Managed Agents Session Thread Usage

- `beta_managed_agents_session_thread_usage: object { cache_creation, cache_read_input_tokens, input_tokens, output_tokens }`

  Cumulative token usage for a session thread across all turns.

  - `cache_creation: optional object { ephemeral_1h_input_tokens, ephemeral_5m_input_tokens }`

    Prompt-cache creation token usage broken down by cache lifetime.

    - `ephemeral_1h_input_tokens: optional number`

      Tokens used to create 1-hour ephemeral cache entries.

    - `ephemeral_5m_input_tokens: optional number`

      Tokens used to create 5-minute ephemeral cache entries.

  - `cache_read_input_tokens: optional number`

    Total tokens read from prompt cache.

  - `input_tokens: optional number`

    Total input tokens consumed across all turns.

  - `output_tokens: optional number`

    Total output tokens generated across all turns.

### Beta Managed Agents Stream Session Thread Events

- `beta_managed_agents_stream_session_thread_events: BetaManagedAgentsUserMessageEvent or BetaManagedAgentsUserInterruptEvent or BetaManagedAgentsUserToolConfirmationEvent or 31 more`

  Server-sent event in a single thread's stream.

  - `beta_managed_agents_user_message_event: object { id, content, type, processed_at }`

    A user message event in the session conversation.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

      Array of content blocks comprising the user message.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

        - `text: string`

          The text content.

        - `type: "text"`

          - `"text"`

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

        - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

          Union type for image source variants.

          - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

            Base64-encoded image data.

            - `data: string`

              Base64-encoded image data.

            - `media_type: string`

              MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

            - `type: "base64"`

              - `"base64"`

          - `beta_managed_agents_url_image_source: object { type, url }`

            Image referenced by URL.

            - `type: "url"`

              - `"url"`

            - `url: string`

              URL of the image to fetch.

          - `beta_managed_agents_file_image_source: object { file_id, type }`

            Image referenced by file ID.

            - `file_id: string`

              ID of a previously uploaded file.

            - `type: "file"`

              - `"file"`

        - `type: "image"`

          - `"image"`

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

          Union type for document source variants.

          - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

            Base64-encoded document data.

            - `data: string`

              Base64-encoded document data.

            - `media_type: string`

              MIME type of the document (e.g., "application/pdf").

            - `type: "base64"`

              - `"base64"`

          - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

            Plain text document content.

            - `data: string`

              The plain text content.

            - `media_type: "text/plain"`

              MIME type of the text content. Must be "text/plain".

              - `"text/plain"`

            - `type: "text"`

              - `"text"`

          - `beta_managed_agents_url_document_source: object { type, url }`

            Document referenced by URL.

            - `type: "url"`

              - `"url"`

            - `url: string`

              URL of the document to fetch.

          - `beta_managed_agents_file_document_source: object { file_id, type }`

            Document referenced by file ID.

            - `file_id: string`

              ID of a previously uploaded file.

            - `type: "file"`

              - `"file"`

        - `type: "document"`

          - `"document"`

        - `context: optional string`

          Additional context about the document for the model.

        - `title: optional string`

          The title of the document.

    - `type: "user.message"`

      - `"user.message"`

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

  - `beta_managed_agents_user_interrupt_event: object { id, type, processed_at, session_thread_id }`

    An interrupt event that pauses agent execution and returns control to the user.

    - `id: string`

      Unique identifier for this event.

    - `type: "user.interrupt"`

      - `"user.interrupt"`

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      If absent, interrupts every non-archived thread in a multiagent session (or the primary alone in a single-agent session). If present, interrupts only the named thread.

  - `beta_managed_agents_user_tool_confirmation_event: object { id, result, tool_use_id, 4 more }`

    A tool confirmation event that approves or denies a pending tool execution.

    - `id: string`

      Unique identifier for this event.

    - `result: "allow" or "deny"`

      UserToolConfirmationResult enum

      - `"allow"`

      - `"deny"`

    - `tool_use_id: string`

      The id of the `agent.tool_use` or `agent.mcp_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: "user.tool_confirmation"`

      - `"user.tool_confirmation"`

    - `deny_message: optional string`

      Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'.

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      When set, the confirmation routes to this subagent's thread rather than the primary. Echo this from the `session_thread_id` on the `agent.tool_use` or `agent.mcp_tool_use` event that prompted the approval.

  - `beta_managed_agents_user_custom_tool_result_event: object { id, custom_tool_use_id, type, 4 more }`

    Event sent by the client providing the result of a custom tool execution.

    - `id: string`

      Unique identifier for this event.

    - `custom_tool_use_id: string`

      The id of the `agent.custom_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: "user.custom_tool_result"`

      - `"user.custom_tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

        - `citations: object { enabled }`

          Citation settings for a search result.

          - `enabled: boolean`

            Whether citations are enabled for this search result.

        - `content: array of BetaManagedAgentsSearchResultContent`

          Array of text content blocks from the search result.

          - `text: string`

            The text content.

          - `type: "text"`

            - `"text"`

        - `source: string`

          The URL source of the search result.

        - `title: string`

          The title of the search result.

        - `type: "search_result"`

          - `"search_result"`

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      Routes this result to a subagent thread. Copy from the `agent.custom_tool_use` event's `session_thread_id`.

  - `beta_managed_agents_agent_custom_tool_use_event: object { id, input, name, 3 more }`

    Event emitted when the agent calls a custom tool. The session goes idle until the client sends a `user.custom_tool_result` event with the result.

    - `id: string`

      Unique identifier for this event.

    - `input: map[unknown]`

      Input parameters for the tool call.

    - `name: string`

      Name of the custom tool being called.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.custom_tool_use"`

      - `"agent.custom_tool_use"`

    - `session_thread_id: optional string`

      When set, this event was cross-posted from a subagent's thread to surface its custom tool use on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.custom_tool_result` event to route the result back.

  - `beta_managed_agents_agent_message_event: object { id, content, processed_at, type }`

    An agent response event in the session conversation.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock`

      Array of text blocks comprising the agent response.

      - `text: string`

        The text content.

      - `type: "text"`

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.message"`

      - `"agent.message"`

  - `beta_managed_agents_agent_thinking_event: object { id, processed_at, type }`

    Indicates the agent is making forward progress via extended thinking. A progress signal, not a content carrier.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.thinking"`

      - `"agent.thinking"`

  - `beta_managed_agents_agent_mcp_tool_use_event: object { id, input, mcp_server_name, 5 more }`

    Event emitted when the agent invokes a tool provided by an MCP server.

    - `id: string`

      Unique identifier for this event.

    - `input: map[unknown]`

      Input parameters for the tool call.

    - `mcp_server_name: string`

      Name of the MCP server providing the tool.

    - `name: string`

      Name of the MCP tool being used.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.mcp_tool_use"`

      - `"agent.mcp_tool_use"`

    - `evaluated_permission: optional "allow" or "ask" or "deny"`

      AgentEvaluatedPermission enum

      - `"allow"`

      - `"ask"`

      - `"deny"`

    - `session_thread_id: optional string`

      When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

  - `beta_managed_agents_agent_mcp_tool_result_event: object { id, mcp_tool_use_id, processed_at, 3 more }`

    Event representing the result of an MCP tool execution.

    - `id: string`

      Unique identifier for this event.

    - `mcp_tool_use_id: string`

      The id of the `agent.mcp_tool_use` event this result corresponds to.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.mcp_tool_result"`

      - `"agent.mcp_tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

  - `beta_managed_agents_agent_tool_use_event: object { id, input, name, 4 more }`

    Event emitted when the agent invokes a built-in agent tool.

    - `id: string`

      Unique identifier for this event.

    - `input: map[unknown]`

      Input parameters for the tool call.

    - `name: string`

      Name of the agent tool being used.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.tool_use"`

      - `"agent.tool_use"`

    - `evaluated_permission: optional "allow" or "ask" or "deny"`

      AgentEvaluatedPermission enum

      - `"allow"`

      - `"ask"`

      - `"deny"`

    - `session_thread_id: optional string`

      When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

  - `beta_managed_agents_agent_tool_result_event: object { id, processed_at, tool_use_id, 3 more }`

    Event representing the result of an agent tool execution.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `tool_use_id: string`

      The id of the `agent.tool_use` event this result corresponds to.

    - `type: "agent.tool_result"`

      - `"agent.tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

  - `beta_managed_agents_agent_thread_message_received_event: object { id, content, from_session_thread_id, 3 more }`

    Delivery event written to the target thread's input stream when an agent-to-agent message arrives.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

      Message content blocks.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

    - `from_session_thread_id: string`

      Public `sthr_` ID of the thread that sent the message.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.thread_message_received"`

      - `"agent.thread_message_received"`

    - `from_agent_name: optional string`

      Name of the callable agent this message came from. Absent when received from the primary agent.

  - `beta_managed_agents_agent_thread_message_sent_event: object { id, content, processed_at, 3 more }`

    Observability event emitted to the sender's output stream when an agent-to-agent message is sent.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

      Message content blocks.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `to_session_thread_id: string`

      Public `sthr_` ID of the thread the message was sent to.

    - `type: "agent.thread_message_sent"`

      - `"agent.thread_message_sent"`

    - `to_agent_name: optional string`

      Name of the callable agent this message was sent to. Absent when sent to the primary agent.

  - `beta_managed_agents_agent_thread_context_compacted_event: object { id, processed_at, type }`

    Indicates that context compaction (summarization) occurred during the session.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.thread_context_compacted"`

      - `"agent.thread_context_compacted"`

  - `beta_managed_agents_session_error_event: object { id, error, processed_at, type }`

    An error event indicating a problem occurred during session execution.

    - `id: string`

      Unique identifier for this event.

    - `error: BetaManagedAgentsUnknownError or BetaManagedAgentsModelOverloadedError or BetaManagedAgentsModelRateLimitedError or 5 more`

      An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

      - `beta_managed_agents_unknown_error: object { message, retry_status, type }`

        An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `type: "retrying"`

              - `"retrying"`

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `type: "exhausted"`

              - `"exhausted"`

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

            - `type: "terminal"`

              - `"terminal"`

        - `type: "unknown_error"`

          - `"unknown_error"`

      - `beta_managed_agents_model_overloaded_error: object { message, retry_status, type }`

        The model is currently overloaded. Emitted after automatic retries are exhausted.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "model_overloaded_error"`

          - `"model_overloaded_error"`

      - `beta_managed_agents_model_rate_limited_error: object { message, retry_status, type }`

        The model request was rate-limited.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "model_rate_limited_error"`

          - `"model_rate_limited_error"`

      - `beta_managed_agents_model_request_failed_error: object { message, retry_status, type }`

        A model request failed for a reason other than overload or rate-limiting.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "model_request_failed_error"`

          - `"model_request_failed_error"`

      - `beta_managed_agents_mcp_connection_failed_error: object { mcp_server_name, message, retry_status, type }`

        Failed to connect to an MCP server.

        - `mcp_server_name: string`

          Name of the MCP server that failed to connect.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "mcp_connection_failed_error"`

          - `"mcp_connection_failed_error"`

      - `beta_managed_agents_mcp_authentication_failed_error: object { mcp_server_name, message, retry_status, type }`

        Authentication to an MCP server failed.

        - `mcp_server_name: string`

          Name of the MCP server that failed authentication.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "mcp_authentication_failed_error"`

          - `"mcp_authentication_failed_error"`

      - `beta_managed_agents_billing_error: object { message, retry_status, type }`

        The caller's organization or workspace cannot make model requests — out of credits or spend limit reached. Retrying with the same credentials will not succeed; the caller must resolve the billing state.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "billing_error"`

          - `"billing_error"`

      - `beta_managed_agents_credential_host_unreachable_error: object { credential_id, message, retry_status, 2 more }`

        An `environment_variable` credential's `auth.networking.allowed_hosts` includes a host the environment's network policy does not permit.

        - `credential_id: string`

          ID of the affected credential.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "credential_host_unreachable_error"`

          - `"credential_host_unreachable_error"`

        - `vault_id: string`

          ID of the vault containing the affected credential.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.error"`

      - `"session.error"`

  - `beta_managed_agents_session_status_rescheduled_event: object { id, processed_at, type }`

    Indicates the session is recovering from an error state and is rescheduled for execution.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.status_rescheduled"`

      - `"session.status_rescheduled"`

  - `beta_managed_agents_session_status_running_event: object { id, processed_at, type }`

    Indicates the session is actively running and the agent is working.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.status_running"`

      - `"session.status_running"`

  - `beta_managed_agents_session_status_idle_event: object { id, processed_at, stop_reason, type }`

    Indicates the agent has paused and is awaiting user input.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `stop_reason: BetaManagedAgentsSessionEndTurn or BetaManagedAgentsSessionRequiresAction or BetaManagedAgentsSessionRetriesExhausted`

      The agent completed its turn naturally and is ready for the next user message.

      - `beta_managed_agents_session_end_turn: object { type }`

        The agent completed its turn naturally and is ready for the next user message.

        - `type: "end_turn"`

          - `"end_turn"`

      - `beta_managed_agents_session_requires_action: object { event_ids, type }`

        The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

        - `event_ids: array of string`

          The ids of events the agent is blocked on. Resolving fewer than all re-emits `session.status_idle` with the remainder.

        - `type: "requires_action"`

          - `"requires_action"`

      - `beta_managed_agents_session_retries_exhausted: object { type }`

        The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

        - `type: "retries_exhausted"`

          - `"retries_exhausted"`

    - `type: "session.status_idle"`

      - `"session.status_idle"`

  - `beta_managed_agents_session_status_terminated_event: object { id, processed_at, type }`

    Indicates the session has terminated, either due to an error or completion.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.status_terminated"`

      - `"session.status_terminated"`

  - `beta_managed_agents_session_thread_created_event: object { id, agent_name, processed_at, 2 more }`

    Emitted when a subagent is spawned as a new thread. Written to the parent thread's output stream so clients observing the session see child creation.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the callable agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public `sthr_` ID of the newly created thread.

    - `type: "session.thread_created"`

      - `"session.thread_created"`

  - `beta_managed_agents_span_outcome_evaluation_start_event: object { id, iteration, outcome_id, 2 more }`

    Emitted when an outcome evaluation cycle begins.

    - `id: string`

      Unique identifier for this event.

    - `iteration: number`

      0-indexed revision cycle. 0 is the first evaluation; 1 is the re-evaluation after the first revision; etc.

    - `outcome_id: string`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.outcome_evaluation_start"`

      - `"span.outcome_evaluation_start"`

  - `beta_managed_agents_span_outcome_evaluation_end_event: object { id, explanation, iteration, 6 more }`

    Emitted when an outcome evaluation cycle completes. Carries the verdict and aggregate token usage. A verdict of `needs_revision` means another evaluation cycle follows; `satisfied`, `max_iterations_reached`, `failed`, or `interrupted` are terminal — no further evaluation cycles follow.

    - `id: string`

      Unique identifier for this event.

    - `explanation: string`

      Human-readable explanation of the verdict. For `needs_revision`, describes which criteria failed and why.

    - `iteration: number`

      0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

    - `outcome_evaluation_start_id: string`

      The id of the corresponding `span.outcome_evaluation_start` event.

    - `outcome_id: string`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `result: string`

      Evaluation verdict. 'satisfied': criteria met, session goes idle. 'needs_revision': criteria not met, another revision cycle follows. 'max_iterations_reached': evaluation budget exhausted with criteria still unmet — one final acknowledgment turn follows before the session goes idle, but no further evaluation runs. 'failed': grader determined the rubric does not apply to the deliverables. 'interrupted': user sent an interrupt while evaluation was in progress.

    - `type: "span.outcome_evaluation_end"`

      - `"span.outcome_evaluation_end"`

    - `usage: object { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }`

      Token usage for a single model request.

      - `cache_creation_input_tokens: number`

        Tokens used to create prompt cache in this request.

      - `cache_read_input_tokens: number`

        Tokens read from prompt cache in this request.

      - `input_tokens: number`

        Input tokens consumed by this request.

      - `output_tokens: number`

        Output tokens generated by this request.

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `"standard"`

        - `"fast"`

  - `beta_managed_agents_span_model_request_start_event: object { id, processed_at, type }`

    Emitted when a model request is initiated by the agent.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.model_request_start"`

      - `"span.model_request_start"`

  - `beta_managed_agents_span_model_request_end_event: object { id, is_error, model_request_start_id, 3 more }`

    Emitted when a model request completes.

    - `id: string`

      Unique identifier for this event.

    - `is_error: boolean`

      Whether the model request resulted in an error.

    - `model_request_start_id: string`

      The id of the corresponding `span.model_request_start` event.

    - `model_usage: object { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }`

      Token usage for a single model request.

      - `cache_creation_input_tokens: number`

        Tokens used to create prompt cache in this request.

      - `cache_read_input_tokens: number`

        Tokens read from prompt cache in this request.

      - `input_tokens: number`

        Input tokens consumed by this request.

      - `output_tokens: number`

        Output tokens generated by this request.

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.model_request_end"`

      - `"span.model_request_end"`

  - `beta_managed_agents_span_outcome_evaluation_ongoing_event: object { id, iteration, outcome_id, 2 more }`

    Periodic heartbeat emitted while an outcome evaluation cycle is in progress. Distinguishes 'evaluation is actively running' from 'evaluation is stuck' between the corresponding `span.outcome_evaluation_start` and `span.outcome_evaluation_end` events.

    - `id: string`

      Unique identifier for this event.

    - `iteration: number`

      0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

    - `outcome_id: string`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.outcome_evaluation_ongoing"`

      - `"span.outcome_evaluation_ongoing"`

  - `beta_managed_agents_user_define_outcome_event: object { id, description, max_iterations, 4 more }`

    Echo of a `user.define_outcome` input event. Carries the server-generated `outcome_id` that subsequent `span.outcome_evaluation_*` events reference.

    - `id: string`

      Unique identifier for this event.

    - `description: string`

      What the agent should produce. Copied from the input event.

    - `max_iterations: number`

      Evaluate-then-revise cycles before giving up. Default 3, max 20.

    - `outcome_id: string`

      Server-generated `outc_` ID for this outcome. Referenced by `span.outcome_evaluation_*` events and the session's `outcome_evaluations` list.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `rubric: BetaManagedAgentsFileRubric or BetaManagedAgentsTextRubric`

      Rubric for grading the quality of an outcome.

      - `beta_managed_agents_file_rubric: object { file_id, type }`

        Rubric referenced by a file uploaded via the Files API.

        - `file_id: string`

          ID of the rubric file.

        - `type: "file"`

          - `"file"`

      - `beta_managed_agents_text_rubric: object { content, type }`

        Rubric content provided inline as text.

        - `content: string`

          Rubric content. Plain text or markdown — the grader treats it as freeform text.

        - `type: "text"`

          - `"text"`

    - `type: "user.define_outcome"`

      - `"user.define_outcome"`

  - `beta_managed_agents_session_deleted_event: object { id, processed_at, type }`

    Emitted when a session has been deleted. Terminates any active event stream — no further events will be emitted for this session.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.deleted"`

      - `"session.deleted"`

  - `beta_managed_agents_session_thread_status_running_event: object { id, agent_name, processed_at, 2 more }`

    A session thread has begun executing. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that started running.

    - `type: "session.thread_status_running"`

      - `"session.thread_status_running"`

  - `beta_managed_agents_session_thread_status_idle_event: object { id, agent_name, processed_at, 3 more }`

    A session thread has yielded and is awaiting input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that went idle.

    - `stop_reason: BetaManagedAgentsSessionEndTurn or BetaManagedAgentsSessionRequiresAction or BetaManagedAgentsSessionRetriesExhausted`

      The agent completed its turn naturally and is ready for the next user message.

      - `beta_managed_agents_session_end_turn: object { type }`

        The agent completed its turn naturally and is ready for the next user message.

      - `beta_managed_agents_session_requires_action: object { event_ids, type }`

        The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

      - `beta_managed_agents_session_retries_exhausted: object { type }`

        The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

    - `type: "session.thread_status_idle"`

      - `"session.thread_status_idle"`

  - `beta_managed_agents_session_thread_status_terminated_event: object { id, agent_name, processed_at, 2 more }`

    A session thread has terminated and will accept no further input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that terminated.

    - `type: "session.thread_status_terminated"`

      - `"session.thread_status_terminated"`

  - `beta_managed_agents_user_tool_result_event: object { id, tool_use_id, type, 4 more }`

    Event sent by the client providing the result of an agent-toolset tool execution. Only valid on `self_hosted` environments, where sandbox-routed tools are executed by the client rather than the server.

    - `id: string`

      Unique identifier for this event.

    - `tool_use_id: string`

      The id of the `agent.tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: "user.tool_result"`

      - `"user.tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      Routes this result to a subagent thread. Copy from the `agent.tool_use` event's `session_thread_id`.

  - `beta_managed_agents_session_thread_status_rescheduled_event: object { id, agent_name, processed_at, 2 more }`

    A session thread hit a transient error and is retrying automatically. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that is retrying.

    - `type: "session.thread_status_rescheduled"`

      - `"session.thread_status_rescheduled"`

  - `beta_managed_agents_session_updated_event: object { id, processed_at, type, 3 more }`

    Emitted when an UpdateSession request changed at least one field. Carries only the fields that changed; absent fields were not part of the update. The new configuration applies from the next turn.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.updated"`

      - `"session.updated"`

    - `agent: optional object { id, description, mcp_servers, 8 more }`

      Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time.

      - `id: string`

      - `description: string`

      - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

        - `name: string`

        - `type: "url"`

          - `"url"`

        - `url: string`

      - `model: object { id, speed }`

        Model identifier and configuration.

        - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

          The model that will power your agent.

          See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

          - `"claude-fable-5"`

            Next generation of intelligence for the hardest knowledge work and coding problems

          - `"claude-opus-4-8"`

            Frontier intelligence for long-running agents and coding

          - `"claude-opus-4-7"`

            Frontier intelligence for long-running agents and coding

          - `"claude-opus-4-6"`

            Most intelligent model for building agents and coding

          - `"claude-sonnet-4-6"`

            Best combination of speed and intelligence

          - `"claude-haiku-4-5"`

            Fastest model with near-frontier intelligence

          - `"claude-haiku-4-5-20251001"`

            Fastest model with near-frontier intelligence

          - `"claude-opus-4-5"`

            Premium model combining maximum intelligence with practical performance

          - `"claude-opus-4-5-20251101"`

            Premium model combining maximum intelligence with practical performance

          - `"claude-sonnet-4-5"`

            High-performance model for agents and coding

          - `"claude-sonnet-4-5-20250929"`

            High-performance model for agents and coding

        - `speed: optional "standard" or "fast"`

          Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

          - `"standard"`

          - `"fast"`

      - `multiagent: object { agents, type }`

        Resolved coordinator topology with full agent definitions for each roster member.

        - `agents: array of BetaManagedAgentsSessionThreadAgent`

          Full `agent` definitions the coordinator may spawn as session threads.

          - `id: string`

          - `description: string`

          - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

            - `name: string`

            - `type: "url"`

            - `url: string`

          - `model: object { id, speed }`

            Model identifier and configuration.

            - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

              The model that will power your agent.

              See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

            - `speed: optional "standard" or "fast"`

              Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

          - `name: string`

          - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

            - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

              A resolved Anthropic-managed skill.

              - `skill_id: string`

              - `type: "anthropic"`

                - `"anthropic"`

              - `version: string`

            - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

              A resolved user-created custom skill.

              - `skill_id: string`

              - `type: "custom"`

                - `"custom"`

              - `version: string`

          - `system: string`

          - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

            - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

              - `configs: array of BetaManagedAgentsAgentToolConfig`

                - `enabled: boolean`

                - `name: "bash" or "edit" or "read" or 5 more`

                  Built-in agent tool identifier.

                  - `"bash"`

                  - `"edit"`

                  - `"read"`

                  - `"write"`

                  - `"glob"`

                  - `"grep"`

                  - `"web_fetch"`

                  - `"web_search"`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                    - `type: "always_allow"`

                      - `"always_allow"`

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

                    - `type: "always_ask"`

                      - `"always_ask"`

              - `default_config: object { enabled, permission_policy }`

                Resolved default configuration for agent tools.

                - `enabled: boolean`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

              - `type: "agent_toolset_20260401"`

                - `"agent_toolset_20260401"`

            - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

              - `configs: array of BetaManagedAgentsMCPToolConfig`

                - `enabled: boolean`

                - `name: string`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

              - `default_config: object { enabled, permission_policy }`

                Resolved default configuration for all tools from an MCP server.

                - `enabled: boolean`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

              - `mcp_server_name: string`

              - `type: "mcp_toolset"`

                - `"mcp_toolset"`

            - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

              A custom tool as returned in API responses.

              - `description: string`

              - `input_schema: object { type, properties, required }`

                JSON Schema for custom tool input parameters.

                - `type: "object"`

                - `properties: optional map[unknown]`

                - `required: optional array of string`

              - `name: string`

              - `type: "custom"`

                - `"custom"`

          - `type: "agent"`

            - `"agent"`

          - `version: number`

        - `type: "coordinator"`

          - `"coordinator"`

      - `name: string`

      - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

        - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

          A resolved Anthropic-managed skill.

        - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

          A resolved user-created custom skill.

      - `system: string`

      - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

        - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

        - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

        - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

          A custom tool as returned in API responses.

      - `type: "agent"`

        - `"agent"`

      - `version: number`

    - `metadata: optional map[string]`

      The session's full metadata bag after the update. Present when the update set non-empty metadata; absent when metadata was unchanged or cleared to empty.

    - `title: optional string`

      The session's new title. Present only when the update changed it.

  - `beta_managed_agents_system_message_event: object { id, content, type, processed_at }`

    A mid-conversation system message event. Carries system-role content that is appended to the session as a `role: "system"` turn.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsSystemContentBlock`

      System content blocks. Text-only.

      - `text: string`

        The text content.

      - `type: "text"`

        - `"text"`

    - `type: "system.message"`

      - `"system.message"`

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

# Events

## List Session Thread Events

`$ ant beta:sessions:threads:events list`

**get** `/v1/sessions/{session_id}/threads/{thread_id}/events`

List Session Thread Events

### Parameters

- `--session-id: string`

  Path param: Path parameter session_id

- `--thread-id: string`

  Path param: Path parameter thread_id

- `--limit: optional number`

  Query param: Query parameter for limit

- `--page: optional string`

  Query param: Query parameter for page

- `--beta: optional array of AnthropicBeta`

  Header param: Optional header to specify the beta version(s) you want to use.

### Returns

- `BetaManagedAgentsListSessionThreadEvents: object { data, next_page }`

  Paginated list of events for a single thread within a `session`.

  - `data: optional array of BetaManagedAgentsSessionEvent`

    Events for the thread, ordered by `created_at`.

    - `beta_managed_agents_user_message_event: object { id, content, type, processed_at }`

      A user message event in the session conversation.

      - `id: string`

        Unique identifier for this event.

      - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

        Array of content blocks comprising the user message.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

          - `text: string`

            The text content.

          - `type: "text"`

            - `"text"`

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

          - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

            Union type for image source variants.

            - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

              Base64-encoded image data.

              - `data: string`

                Base64-encoded image data.

              - `media_type: string`

                MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

              - `type: "base64"`

                - `"base64"`

            - `beta_managed_agents_url_image_source: object { type, url }`

              Image referenced by URL.

              - `type: "url"`

                - `"url"`

              - `url: string`

                URL of the image to fetch.

            - `beta_managed_agents_file_image_source: object { file_id, type }`

              Image referenced by file ID.

              - `file_id: string`

                ID of a previously uploaded file.

              - `type: "file"`

                - `"file"`

          - `type: "image"`

            - `"image"`

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

          - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

            Union type for document source variants.

            - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

              Base64-encoded document data.

              - `data: string`

                Base64-encoded document data.

              - `media_type: string`

                MIME type of the document (e.g., "application/pdf").

              - `type: "base64"`

                - `"base64"`

            - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

              Plain text document content.

              - `data: string`

                The plain text content.

              - `media_type: "text/plain"`

                MIME type of the text content. Must be "text/plain".

                - `"text/plain"`

              - `type: "text"`

                - `"text"`

            - `beta_managed_agents_url_document_source: object { type, url }`

              Document referenced by URL.

              - `type: "url"`

                - `"url"`

              - `url: string`

                URL of the document to fetch.

            - `beta_managed_agents_file_document_source: object { file_id, type }`

              Document referenced by file ID.

              - `file_id: string`

                ID of a previously uploaded file.

              - `type: "file"`

                - `"file"`

          - `type: "document"`

            - `"document"`

          - `context: optional string`

            Additional context about the document for the model.

          - `title: optional string`

            The title of the document.

      - `type: "user.message"`

        - `"user.message"`

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

    - `beta_managed_agents_user_interrupt_event: object { id, type, processed_at, session_thread_id }`

      An interrupt event that pauses agent execution and returns control to the user.

      - `id: string`

        Unique identifier for this event.

      - `type: "user.interrupt"`

        - `"user.interrupt"`

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

      - `session_thread_id: optional string`

        If absent, interrupts every non-archived thread in a multiagent session (or the primary alone in a single-agent session). If present, interrupts only the named thread.

    - `beta_managed_agents_user_tool_confirmation_event: object { id, result, tool_use_id, 4 more }`

      A tool confirmation event that approves or denies a pending tool execution.

      - `id: string`

        Unique identifier for this event.

      - `result: "allow" or "deny"`

        UserToolConfirmationResult enum

        - `"allow"`

        - `"deny"`

      - `tool_use_id: string`

        The id of the `agent.tool_use` or `agent.mcp_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

      - `type: "user.tool_confirmation"`

        - `"user.tool_confirmation"`

      - `deny_message: optional string`

        Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'.

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

      - `session_thread_id: optional string`

        When set, the confirmation routes to this subagent's thread rather than the primary. Echo this from the `session_thread_id` on the `agent.tool_use` or `agent.mcp_tool_use` event that prompted the approval.

    - `beta_managed_agents_user_custom_tool_result_event: object { id, custom_tool_use_id, type, 4 more }`

      Event sent by the client providing the result of a custom tool execution.

      - `id: string`

        Unique identifier for this event.

      - `custom_tool_use_id: string`

        The id of the `agent.custom_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

      - `type: "user.custom_tool_result"`

        - `"user.custom_tool_result"`

      - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

        The result content returned by the tool.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

          A block containing a web search result.

          - `citations: object { enabled }`

            Citation settings for a search result.

            - `enabled: boolean`

              Whether citations are enabled for this search result.

          - `content: array of BetaManagedAgentsSearchResultContent`

            Array of text content blocks from the search result.

            - `text: string`

              The text content.

            - `type: "text"`

              - `"text"`

          - `source: string`

            The URL source of the search result.

          - `title: string`

            The title of the search result.

          - `type: "search_result"`

            - `"search_result"`

      - `is_error: optional boolean`

        Whether the tool execution resulted in an error.

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

      - `session_thread_id: optional string`

        Routes this result to a subagent thread. Copy from the `agent.custom_tool_use` event's `session_thread_id`.

    - `beta_managed_agents_agent_custom_tool_use_event: object { id, input, name, 3 more }`

      Event emitted when the agent calls a custom tool. The session goes idle until the client sends a `user.custom_tool_result` event with the result.

      - `id: string`

        Unique identifier for this event.

      - `input: map[unknown]`

        Input parameters for the tool call.

      - `name: string`

        Name of the custom tool being called.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "agent.custom_tool_use"`

        - `"agent.custom_tool_use"`

      - `session_thread_id: optional string`

        When set, this event was cross-posted from a subagent's thread to surface its custom tool use on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.custom_tool_result` event to route the result back.

    - `beta_managed_agents_agent_message_event: object { id, content, processed_at, type }`

      An agent response event in the session conversation.

      - `id: string`

        Unique identifier for this event.

      - `content: array of BetaManagedAgentsTextBlock`

        Array of text blocks comprising the agent response.

        - `text: string`

          The text content.

        - `type: "text"`

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "agent.message"`

        - `"agent.message"`

    - `beta_managed_agents_agent_thinking_event: object { id, processed_at, type }`

      Indicates the agent is making forward progress via extended thinking. A progress signal, not a content carrier.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "agent.thinking"`

        - `"agent.thinking"`

    - `beta_managed_agents_agent_mcp_tool_use_event: object { id, input, mcp_server_name, 5 more }`

      Event emitted when the agent invokes a tool provided by an MCP server.

      - `id: string`

        Unique identifier for this event.

      - `input: map[unknown]`

        Input parameters for the tool call.

      - `mcp_server_name: string`

        Name of the MCP server providing the tool.

      - `name: string`

        Name of the MCP tool being used.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "agent.mcp_tool_use"`

        - `"agent.mcp_tool_use"`

      - `evaluated_permission: optional "allow" or "ask" or "deny"`

        AgentEvaluatedPermission enum

        - `"allow"`

        - `"ask"`

        - `"deny"`

      - `session_thread_id: optional string`

        When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

    - `beta_managed_agents_agent_mcp_tool_result_event: object { id, mcp_tool_use_id, processed_at, 3 more }`

      Event representing the result of an MCP tool execution.

      - `id: string`

        Unique identifier for this event.

      - `mcp_tool_use_id: string`

        The id of the `agent.mcp_tool_use` event this result corresponds to.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "agent.mcp_tool_result"`

        - `"agent.mcp_tool_result"`

      - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

        The result content returned by the tool.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

          A block containing a web search result.

      - `is_error: optional boolean`

        Whether the tool execution resulted in an error.

    - `beta_managed_agents_agent_tool_use_event: object { id, input, name, 4 more }`

      Event emitted when the agent invokes a built-in agent tool.

      - `id: string`

        Unique identifier for this event.

      - `input: map[unknown]`

        Input parameters for the tool call.

      - `name: string`

        Name of the agent tool being used.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "agent.tool_use"`

        - `"agent.tool_use"`

      - `evaluated_permission: optional "allow" or "ask" or "deny"`

        AgentEvaluatedPermission enum

        - `"allow"`

        - `"ask"`

        - `"deny"`

      - `session_thread_id: optional string`

        When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

    - `beta_managed_agents_agent_tool_result_event: object { id, processed_at, tool_use_id, 3 more }`

      Event representing the result of an agent tool execution.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `tool_use_id: string`

        The id of the `agent.tool_use` event this result corresponds to.

      - `type: "agent.tool_result"`

        - `"agent.tool_result"`

      - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

        The result content returned by the tool.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

          A block containing a web search result.

      - `is_error: optional boolean`

        Whether the tool execution resulted in an error.

    - `beta_managed_agents_agent_thread_message_received_event: object { id, content, from_session_thread_id, 3 more }`

      Delivery event written to the target thread's input stream when an agent-to-agent message arrives.

      - `id: string`

        Unique identifier for this event.

      - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

        Message content blocks.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `from_session_thread_id: string`

        Public `sthr_` ID of the thread that sent the message.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "agent.thread_message_received"`

        - `"agent.thread_message_received"`

      - `from_agent_name: optional string`

        Name of the callable agent this message came from. Absent when received from the primary agent.

    - `beta_managed_agents_agent_thread_message_sent_event: object { id, content, processed_at, 3 more }`

      Observability event emitted to the sender's output stream when an agent-to-agent message is sent.

      - `id: string`

        Unique identifier for this event.

      - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

        Message content blocks.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `to_session_thread_id: string`

        Public `sthr_` ID of the thread the message was sent to.

      - `type: "agent.thread_message_sent"`

        - `"agent.thread_message_sent"`

      - `to_agent_name: optional string`

        Name of the callable agent this message was sent to. Absent when sent to the primary agent.

    - `beta_managed_agents_agent_thread_context_compacted_event: object { id, processed_at, type }`

      Indicates that context compaction (summarization) occurred during the session.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "agent.thread_context_compacted"`

        - `"agent.thread_context_compacted"`

    - `beta_managed_agents_session_error_event: object { id, error, processed_at, type }`

      An error event indicating a problem occurred during session execution.

      - `id: string`

        Unique identifier for this event.

      - `error: BetaManagedAgentsUnknownError or BetaManagedAgentsModelOverloadedError or BetaManagedAgentsModelRateLimitedError or 5 more`

        An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

        - `beta_managed_agents_unknown_error: object { message, retry_status, type }`

          An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

          - `message: string`

            Human-readable error description.

          - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

            What the client should do next in response to this error.

            - `beta_managed_agents_retry_status_retrying: object { type }`

              The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

              - `type: "retrying"`

                - `"retrying"`

            - `beta_managed_agents_retry_status_exhausted: object { type }`

              This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

              - `type: "exhausted"`

                - `"exhausted"`

            - `beta_managed_agents_retry_status_terminal: object { type }`

              The session encountered a terminal error and will transition to `terminated` state.

              - `type: "terminal"`

                - `"terminal"`

          - `type: "unknown_error"`

            - `"unknown_error"`

        - `beta_managed_agents_model_overloaded_error: object { message, retry_status, type }`

          The model is currently overloaded. Emitted after automatic retries are exhausted.

          - `message: string`

            Human-readable error description.

          - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

            What the client should do next in response to this error.

            - `beta_managed_agents_retry_status_retrying: object { type }`

              The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `beta_managed_agents_retry_status_exhausted: object { type }`

              This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `beta_managed_agents_retry_status_terminal: object { type }`

              The session encountered a terminal error and will transition to `terminated` state.

          - `type: "model_overloaded_error"`

            - `"model_overloaded_error"`

        - `beta_managed_agents_model_rate_limited_error: object { message, retry_status, type }`

          The model request was rate-limited.

          - `message: string`

            Human-readable error description.

          - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

            What the client should do next in response to this error.

            - `beta_managed_agents_retry_status_retrying: object { type }`

              The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `beta_managed_agents_retry_status_exhausted: object { type }`

              This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `beta_managed_agents_retry_status_terminal: object { type }`

              The session encountered a terminal error and will transition to `terminated` state.

          - `type: "model_rate_limited_error"`

            - `"model_rate_limited_error"`

        - `beta_managed_agents_model_request_failed_error: object { message, retry_status, type }`

          A model request failed for a reason other than overload or rate-limiting.

          - `message: string`

            Human-readable error description.

          - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

            What the client should do next in response to this error.

            - `beta_managed_agents_retry_status_retrying: object { type }`

              The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `beta_managed_agents_retry_status_exhausted: object { type }`

              This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `beta_managed_agents_retry_status_terminal: object { type }`

              The session encountered a terminal error and will transition to `terminated` state.

          - `type: "model_request_failed_error"`

            - `"model_request_failed_error"`

        - `beta_managed_agents_mcp_connection_failed_error: object { mcp_server_name, message, retry_status, type }`

          Failed to connect to an MCP server.

          - `mcp_server_name: string`

            Name of the MCP server that failed to connect.

          - `message: string`

            Human-readable error description.

          - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

            What the client should do next in response to this error.

            - `beta_managed_agents_retry_status_retrying: object { type }`

              The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `beta_managed_agents_retry_status_exhausted: object { type }`

              This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `beta_managed_agents_retry_status_terminal: object { type }`

              The session encountered a terminal error and will transition to `terminated` state.

          - `type: "mcp_connection_failed_error"`

            - `"mcp_connection_failed_error"`

        - `beta_managed_agents_mcp_authentication_failed_error: object { mcp_server_name, message, retry_status, type }`

          Authentication to an MCP server failed.

          - `mcp_server_name: string`

            Name of the MCP server that failed authentication.

          - `message: string`

            Human-readable error description.

          - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

            What the client should do next in response to this error.

            - `beta_managed_agents_retry_status_retrying: object { type }`

              The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `beta_managed_agents_retry_status_exhausted: object { type }`

              This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `beta_managed_agents_retry_status_terminal: object { type }`

              The session encountered a terminal error and will transition to `terminated` state.

          - `type: "mcp_authentication_failed_error"`

            - `"mcp_authentication_failed_error"`

        - `beta_managed_agents_billing_error: object { message, retry_status, type }`

          The caller's organization or workspace cannot make model requests — out of credits or spend limit reached. Retrying with the same credentials will not succeed; the caller must resolve the billing state.

          - `message: string`

            Human-readable error description.

          - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

            What the client should do next in response to this error.

            - `beta_managed_agents_retry_status_retrying: object { type }`

              The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `beta_managed_agents_retry_status_exhausted: object { type }`

              This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `beta_managed_agents_retry_status_terminal: object { type }`

              The session encountered a terminal error and will transition to `terminated` state.

          - `type: "billing_error"`

            - `"billing_error"`

        - `beta_managed_agents_credential_host_unreachable_error: object { credential_id, message, retry_status, 2 more }`

          An `environment_variable` credential's `auth.networking.allowed_hosts` includes a host the environment's network policy does not permit.

          - `credential_id: string`

            ID of the affected credential.

          - `message: string`

            Human-readable error description.

          - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

            What the client should do next in response to this error.

            - `beta_managed_agents_retry_status_retrying: object { type }`

              The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `beta_managed_agents_retry_status_exhausted: object { type }`

              This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `beta_managed_agents_retry_status_terminal: object { type }`

              The session encountered a terminal error and will transition to `terminated` state.

          - `type: "credential_host_unreachable_error"`

            - `"credential_host_unreachable_error"`

          - `vault_id: string`

            ID of the vault containing the affected credential.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "session.error"`

        - `"session.error"`

    - `beta_managed_agents_session_status_rescheduled_event: object { id, processed_at, type }`

      Indicates the session is recovering from an error state and is rescheduled for execution.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "session.status_rescheduled"`

        - `"session.status_rescheduled"`

    - `beta_managed_agents_session_status_running_event: object { id, processed_at, type }`

      Indicates the session is actively running and the agent is working.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "session.status_running"`

        - `"session.status_running"`

    - `beta_managed_agents_session_status_idle_event: object { id, processed_at, stop_reason, type }`

      Indicates the agent has paused and is awaiting user input.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `stop_reason: BetaManagedAgentsSessionEndTurn or BetaManagedAgentsSessionRequiresAction or BetaManagedAgentsSessionRetriesExhausted`

        The agent completed its turn naturally and is ready for the next user message.

        - `beta_managed_agents_session_end_turn: object { type }`

          The agent completed its turn naturally and is ready for the next user message.

          - `type: "end_turn"`

            - `"end_turn"`

        - `beta_managed_agents_session_requires_action: object { event_ids, type }`

          The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

          - `event_ids: array of string`

            The ids of events the agent is blocked on. Resolving fewer than all re-emits `session.status_idle` with the remainder.

          - `type: "requires_action"`

            - `"requires_action"`

        - `beta_managed_agents_session_retries_exhausted: object { type }`

          The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

          - `type: "retries_exhausted"`

            - `"retries_exhausted"`

      - `type: "session.status_idle"`

        - `"session.status_idle"`

    - `beta_managed_agents_session_status_terminated_event: object { id, processed_at, type }`

      Indicates the session has terminated, either due to an error or completion.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "session.status_terminated"`

        - `"session.status_terminated"`

    - `beta_managed_agents_session_thread_created_event: object { id, agent_name, processed_at, 2 more }`

      Emitted when a subagent is spawned as a new thread. Written to the parent thread's output stream so clients observing the session see child creation.

      - `id: string`

        Unique identifier for this event.

      - `agent_name: string`

        Name of the callable agent the thread runs.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `session_thread_id: string`

        Public `sthr_` ID of the newly created thread.

      - `type: "session.thread_created"`

        - `"session.thread_created"`

    - `beta_managed_agents_span_outcome_evaluation_start_event: object { id, iteration, outcome_id, 2 more }`

      Emitted when an outcome evaluation cycle begins.

      - `id: string`

        Unique identifier for this event.

      - `iteration: number`

        0-indexed revision cycle. 0 is the first evaluation; 1 is the re-evaluation after the first revision; etc.

      - `outcome_id: string`

        The `outc_` ID of the outcome being evaluated.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "span.outcome_evaluation_start"`

        - `"span.outcome_evaluation_start"`

    - `beta_managed_agents_span_outcome_evaluation_end_event: object { id, explanation, iteration, 6 more }`

      Emitted when an outcome evaluation cycle completes. Carries the verdict and aggregate token usage. A verdict of `needs_revision` means another evaluation cycle follows; `satisfied`, `max_iterations_reached`, `failed`, or `interrupted` are terminal — no further evaluation cycles follow.

      - `id: string`

        Unique identifier for this event.

      - `explanation: string`

        Human-readable explanation of the verdict. For `needs_revision`, describes which criteria failed and why.

      - `iteration: number`

        0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

      - `outcome_evaluation_start_id: string`

        The id of the corresponding `span.outcome_evaluation_start` event.

      - `outcome_id: string`

        The `outc_` ID of the outcome being evaluated.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `result: string`

        Evaluation verdict. 'satisfied': criteria met, session goes idle. 'needs_revision': criteria not met, another revision cycle follows. 'max_iterations_reached': evaluation budget exhausted with criteria still unmet — one final acknowledgment turn follows before the session goes idle, but no further evaluation runs. 'failed': grader determined the rubric does not apply to the deliverables. 'interrupted': user sent an interrupt while evaluation was in progress.

      - `type: "span.outcome_evaluation_end"`

        - `"span.outcome_evaluation_end"`

      - `usage: object { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }`

        Token usage for a single model request.

        - `cache_creation_input_tokens: number`

          Tokens used to create prompt cache in this request.

        - `cache_read_input_tokens: number`

          Tokens read from prompt cache in this request.

        - `input_tokens: number`

          Input tokens consumed by this request.

        - `output_tokens: number`

          Output tokens generated by this request.

        - `speed: optional "standard" or "fast"`

          Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

          - `"standard"`

          - `"fast"`

    - `beta_managed_agents_span_model_request_start_event: object { id, processed_at, type }`

      Emitted when a model request is initiated by the agent.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "span.model_request_start"`

        - `"span.model_request_start"`

    - `beta_managed_agents_span_model_request_end_event: object { id, is_error, model_request_start_id, 3 more }`

      Emitted when a model request completes.

      - `id: string`

        Unique identifier for this event.

      - `is_error: boolean`

        Whether the model request resulted in an error.

      - `model_request_start_id: string`

        The id of the corresponding `span.model_request_start` event.

      - `model_usage: object { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }`

        Token usage for a single model request.

        - `cache_creation_input_tokens: number`

          Tokens used to create prompt cache in this request.

        - `cache_read_input_tokens: number`

          Tokens read from prompt cache in this request.

        - `input_tokens: number`

          Input tokens consumed by this request.

        - `output_tokens: number`

          Output tokens generated by this request.

        - `speed: optional "standard" or "fast"`

          Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "span.model_request_end"`

        - `"span.model_request_end"`

    - `beta_managed_agents_span_outcome_evaluation_ongoing_event: object { id, iteration, outcome_id, 2 more }`

      Periodic heartbeat emitted while an outcome evaluation cycle is in progress. Distinguishes 'evaluation is actively running' from 'evaluation is stuck' between the corresponding `span.outcome_evaluation_start` and `span.outcome_evaluation_end` events.

      - `id: string`

        Unique identifier for this event.

      - `iteration: number`

        0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

      - `outcome_id: string`

        The `outc_` ID of the outcome being evaluated.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "span.outcome_evaluation_ongoing"`

        - `"span.outcome_evaluation_ongoing"`

    - `beta_managed_agents_user_define_outcome_event: object { id, description, max_iterations, 4 more }`

      Echo of a `user.define_outcome` input event. Carries the server-generated `outcome_id` that subsequent `span.outcome_evaluation_*` events reference.

      - `id: string`

        Unique identifier for this event.

      - `description: string`

        What the agent should produce. Copied from the input event.

      - `max_iterations: number`

        Evaluate-then-revise cycles before giving up. Default 3, max 20.

      - `outcome_id: string`

        Server-generated `outc_` ID for this outcome. Referenced by `span.outcome_evaluation_*` events and the session's `outcome_evaluations` list.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `rubric: BetaManagedAgentsFileRubric or BetaManagedAgentsTextRubric`

        Rubric for grading the quality of an outcome.

        - `beta_managed_agents_file_rubric: object { file_id, type }`

          Rubric referenced by a file uploaded via the Files API.

          - `file_id: string`

            ID of the rubric file.

          - `type: "file"`

            - `"file"`

        - `beta_managed_agents_text_rubric: object { content, type }`

          Rubric content provided inline as text.

          - `content: string`

            Rubric content. Plain text or markdown — the grader treats it as freeform text.

          - `type: "text"`

            - `"text"`

      - `type: "user.define_outcome"`

        - `"user.define_outcome"`

    - `beta_managed_agents_session_deleted_event: object { id, processed_at, type }`

      Emitted when a session has been deleted. Terminates any active event stream — no further events will be emitted for this session.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "session.deleted"`

        - `"session.deleted"`

    - `beta_managed_agents_session_thread_status_running_event: object { id, agent_name, processed_at, 2 more }`

      A session thread has begun executing. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

      - `id: string`

        Unique identifier for this event.

      - `agent_name: string`

        Name of the agent the thread runs.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `session_thread_id: string`

        Public sthr_ ID of the thread that started running.

      - `type: "session.thread_status_running"`

        - `"session.thread_status_running"`

    - `beta_managed_agents_session_thread_status_idle_event: object { id, agent_name, processed_at, 3 more }`

      A session thread has yielded and is awaiting input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

      - `id: string`

        Unique identifier for this event.

      - `agent_name: string`

        Name of the agent the thread runs.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `session_thread_id: string`

        Public sthr_ ID of the thread that went idle.

      - `stop_reason: BetaManagedAgentsSessionEndTurn or BetaManagedAgentsSessionRequiresAction or BetaManagedAgentsSessionRetriesExhausted`

        The agent completed its turn naturally and is ready for the next user message.

        - `beta_managed_agents_session_end_turn: object { type }`

          The agent completed its turn naturally and is ready for the next user message.

        - `beta_managed_agents_session_requires_action: object { event_ids, type }`

          The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

        - `beta_managed_agents_session_retries_exhausted: object { type }`

          The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

      - `type: "session.thread_status_idle"`

        - `"session.thread_status_idle"`

    - `beta_managed_agents_session_thread_status_terminated_event: object { id, agent_name, processed_at, 2 more }`

      A session thread has terminated and will accept no further input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

      - `id: string`

        Unique identifier for this event.

      - `agent_name: string`

        Name of the agent the thread runs.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `session_thread_id: string`

        Public sthr_ ID of the thread that terminated.

      - `type: "session.thread_status_terminated"`

        - `"session.thread_status_terminated"`

    - `beta_managed_agents_user_tool_result_event: object { id, tool_use_id, type, 4 more }`

      Event sent by the client providing the result of an agent-toolset tool execution. Only valid on `self_hosted` environments, where sandbox-routed tools are executed by the client rather than the server.

      - `id: string`

        Unique identifier for this event.

      - `tool_use_id: string`

        The id of the `agent.tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

      - `type: "user.tool_result"`

        - `"user.tool_result"`

      - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

        The result content returned by the tool.

        - `beta_managed_agents_text_block: object { text, type }`

          Regular text content.

        - `beta_managed_agents_image_block: object { source, type }`

          Image content specified directly as base64 data or as a reference via a URL.

        - `beta_managed_agents_document_block: object { source, type, context, title }`

          Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

          A block containing a web search result.

      - `is_error: optional boolean`

        Whether the tool execution resulted in an error.

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

      - `session_thread_id: optional string`

        Routes this result to a subagent thread. Copy from the `agent.tool_use` event's `session_thread_id`.

    - `beta_managed_agents_session_thread_status_rescheduled_event: object { id, agent_name, processed_at, 2 more }`

      A session thread hit a transient error and is retrying automatically. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

      - `id: string`

        Unique identifier for this event.

      - `agent_name: string`

        Name of the agent the thread runs.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `session_thread_id: string`

        Public sthr_ ID of the thread that is retrying.

      - `type: "session.thread_status_rescheduled"`

        - `"session.thread_status_rescheduled"`

    - `beta_managed_agents_session_updated_event: object { id, processed_at, type, 3 more }`

      Emitted when an UpdateSession request changed at least one field. Carries only the fields that changed; absent fields were not part of the update. The new configuration applies from the next turn.

      - `id: string`

        Unique identifier for this event.

      - `processed_at: string`

        A timestamp in RFC 3339 format

      - `type: "session.updated"`

        - `"session.updated"`

      - `agent: optional object { id, description, mcp_servers, 8 more }`

        Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time.

        - `id: string`

        - `description: string`

        - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

          - `name: string`

          - `type: "url"`

            - `"url"`

          - `url: string`

        - `model: object { id, speed }`

          Model identifier and configuration.

          - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

            The model that will power your agent.

            See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

            - `"claude-fable-5"`

              Next generation of intelligence for the hardest knowledge work and coding problems

            - `"claude-opus-4-8"`

              Frontier intelligence for long-running agents and coding

            - `"claude-opus-4-7"`

              Frontier intelligence for long-running agents and coding

            - `"claude-opus-4-6"`

              Most intelligent model for building agents and coding

            - `"claude-sonnet-4-6"`

              Best combination of speed and intelligence

            - `"claude-haiku-4-5"`

              Fastest model with near-frontier intelligence

            - `"claude-haiku-4-5-20251001"`

              Fastest model with near-frontier intelligence

            - `"claude-opus-4-5"`

              Premium model combining maximum intelligence with practical performance

            - `"claude-opus-4-5-20251101"`

              Premium model combining maximum intelligence with practical performance

            - `"claude-sonnet-4-5"`

              High-performance model for agents and coding

            - `"claude-sonnet-4-5-20250929"`

              High-performance model for agents and coding

          - `speed: optional "standard" or "fast"`

            Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

            - `"standard"`

            - `"fast"`

        - `multiagent: object { agents, type }`

          Resolved coordinator topology with full agent definitions for each roster member.

          - `agents: array of BetaManagedAgentsSessionThreadAgent`

            Full `agent` definitions the coordinator may spawn as session threads.

            - `id: string`

            - `description: string`

            - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

              - `name: string`

              - `type: "url"`

              - `url: string`

            - `model: object { id, speed }`

              Model identifier and configuration.

              - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

                The model that will power your agent.

                See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

              - `speed: optional "standard" or "fast"`

                Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

            - `name: string`

            - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

              - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

                A resolved Anthropic-managed skill.

                - `skill_id: string`

                - `type: "anthropic"`

                  - `"anthropic"`

                - `version: string`

              - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

                A resolved user-created custom skill.

                - `skill_id: string`

                - `type: "custom"`

                  - `"custom"`

                - `version: string`

            - `system: string`

            - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

              - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

                - `configs: array of BetaManagedAgentsAgentToolConfig`

                  - `enabled: boolean`

                  - `name: "bash" or "edit" or "read" or 5 more`

                    Built-in agent tool identifier.

                    - `"bash"`

                    - `"edit"`

                    - `"read"`

                    - `"write"`

                    - `"glob"`

                    - `"grep"`

                    - `"web_fetch"`

                    - `"web_search"`

                  - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                    Permission policy for tool execution.

                    - `beta_managed_agents_always_allow_policy: object { type }`

                      Tool calls are automatically approved without user confirmation.

                      - `type: "always_allow"`

                        - `"always_allow"`

                    - `beta_managed_agents_always_ask_policy: object { type }`

                      Tool calls require user confirmation before execution.

                      - `type: "always_ask"`

                        - `"always_ask"`

                - `default_config: object { enabled, permission_policy }`

                  Resolved default configuration for agent tools.

                  - `enabled: boolean`

                  - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                    Permission policy for tool execution.

                    - `beta_managed_agents_always_allow_policy: object { type }`

                      Tool calls are automatically approved without user confirmation.

                    - `beta_managed_agents_always_ask_policy: object { type }`

                      Tool calls require user confirmation before execution.

                - `type: "agent_toolset_20260401"`

                  - `"agent_toolset_20260401"`

              - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

                - `configs: array of BetaManagedAgentsMCPToolConfig`

                  - `enabled: boolean`

                  - `name: string`

                  - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                    Permission policy for tool execution.

                    - `beta_managed_agents_always_allow_policy: object { type }`

                      Tool calls are automatically approved without user confirmation.

                    - `beta_managed_agents_always_ask_policy: object { type }`

                      Tool calls require user confirmation before execution.

                - `default_config: object { enabled, permission_policy }`

                  Resolved default configuration for all tools from an MCP server.

                  - `enabled: boolean`

                  - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                    Permission policy for tool execution.

                    - `beta_managed_agents_always_allow_policy: object { type }`

                      Tool calls are automatically approved without user confirmation.

                    - `beta_managed_agents_always_ask_policy: object { type }`

                      Tool calls require user confirmation before execution.

                - `mcp_server_name: string`

                - `type: "mcp_toolset"`

                  - `"mcp_toolset"`

              - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

                A custom tool as returned in API responses.

                - `description: string`

                - `input_schema: object { type, properties, required }`

                  JSON Schema for custom tool input parameters.

                  - `type: "object"`

                  - `properties: optional map[unknown]`

                  - `required: optional array of string`

                - `name: string`

                - `type: "custom"`

                  - `"custom"`

            - `type: "agent"`

              - `"agent"`

            - `version: number`

          - `type: "coordinator"`

            - `"coordinator"`

        - `name: string`

        - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

          - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

            A resolved Anthropic-managed skill.

          - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

            A resolved user-created custom skill.

        - `system: string`

        - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

          - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

          - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

          - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

            A custom tool as returned in API responses.

        - `type: "agent"`

          - `"agent"`

        - `version: number`

      - `metadata: optional map[string]`

        The session's full metadata bag after the update. Present when the update set non-empty metadata; absent when metadata was unchanged or cleared to empty.

      - `title: optional string`

        The session's new title. Present only when the update changed it.

    - `beta_managed_agents_system_message_event: object { id, content, type, processed_at }`

      A mid-conversation system message event. Carries system-role content that is appended to the session as a `role: "system"` turn.

      - `id: string`

        Unique identifier for this event.

      - `content: array of BetaManagedAgentsSystemContentBlock`

        System content blocks. Text-only.

        - `text: string`

          The text content.

        - `type: "text"`

          - `"text"`

      - `type: "system.message"`

        - `"system.message"`

      - `processed_at: optional string`

        A timestamp in RFC 3339 format

  - `next_page: optional string`

    Opaque cursor for the next page. Null when no more results.

### Example

```cli
ant beta:sessions:threads:events list \
  --api-key my-anthropic-api-key \
  --session-id sesn_011CZkZAtmR3yMPDzynEDxu7 \
  --thread-id sthr_011CZkZVWa6oIjw0rgXZpnBt
```

#### Response

```json
{
  "data": [
    {
      "id": "sevt_011CZkZGOp0iBcp4kaQSihUmy",
      "content": [
        {
          "text": "Where is my order #1234?",
          "type": "text"
        }
      ],
      "type": "user.message",
      "processed_at": "2026-03-15T10:00:00Z"
    }
  ],
  "next_page": "next_page"
}
```

## Stream Session Thread Events

`$ ant beta:sessions:threads:events stream`

**get** `/v1/sessions/{session_id}/threads/{thread_id}/stream`

Stream Session Thread Events

### Parameters

- `--session-id: string`

  Path param: Path parameter session_id

- `--thread-id: string`

  Path param: Path parameter thread_id

- `--beta: optional array of AnthropicBeta`

  Header param: Optional header to specify the beta version(s) you want to use.

### Returns

- `beta_managed_agents_stream_session_thread_events: BetaManagedAgentsUserMessageEvent or BetaManagedAgentsUserInterruptEvent or BetaManagedAgentsUserToolConfirmationEvent or 31 more`

  Server-sent event in a single thread's stream.

  - `beta_managed_agents_user_message_event: object { id, content, type, processed_at }`

    A user message event in the session conversation.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

      Array of content blocks comprising the user message.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

        - `text: string`

          The text content.

        - `type: "text"`

          - `"text"`

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

        - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`

          Union type for image source variants.

          - `beta_managed_agents_base64_image_source: object { data, media_type, type }`

            Base64-encoded image data.

            - `data: string`

              Base64-encoded image data.

            - `media_type: string`

              MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

            - `type: "base64"`

              - `"base64"`

          - `beta_managed_agents_url_image_source: object { type, url }`

            Image referenced by URL.

            - `type: "url"`

              - `"url"`

            - `url: string`

              URL of the image to fetch.

          - `beta_managed_agents_file_image_source: object { file_id, type }`

            Image referenced by file ID.

            - `file_id: string`

              ID of a previously uploaded file.

            - `type: "file"`

              - `"file"`

        - `type: "image"`

          - `"image"`

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`

          Union type for document source variants.

          - `beta_managed_agents_base64_document_source: object { data, media_type, type }`

            Base64-encoded document data.

            - `data: string`

              Base64-encoded document data.

            - `media_type: string`

              MIME type of the document (e.g., "application/pdf").

            - `type: "base64"`

              - `"base64"`

          - `beta_managed_agents_plain_text_document_source: object { data, media_type, type }`

            Plain text document content.

            - `data: string`

              The plain text content.

            - `media_type: "text/plain"`

              MIME type of the text content. Must be "text/plain".

              - `"text/plain"`

            - `type: "text"`

              - `"text"`

          - `beta_managed_agents_url_document_source: object { type, url }`

            Document referenced by URL.

            - `type: "url"`

              - `"url"`

            - `url: string`

              URL of the document to fetch.

          - `beta_managed_agents_file_document_source: object { file_id, type }`

            Document referenced by file ID.

            - `file_id: string`

              ID of a previously uploaded file.

            - `type: "file"`

              - `"file"`

        - `type: "document"`

          - `"document"`

        - `context: optional string`

          Additional context about the document for the model.

        - `title: optional string`

          The title of the document.

    - `type: "user.message"`

      - `"user.message"`

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

  - `beta_managed_agents_user_interrupt_event: object { id, type, processed_at, session_thread_id }`

    An interrupt event that pauses agent execution and returns control to the user.

    - `id: string`

      Unique identifier for this event.

    - `type: "user.interrupt"`

      - `"user.interrupt"`

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      If absent, interrupts every non-archived thread in a multiagent session (or the primary alone in a single-agent session). If present, interrupts only the named thread.

  - `beta_managed_agents_user_tool_confirmation_event: object { id, result, tool_use_id, 4 more }`

    A tool confirmation event that approves or denies a pending tool execution.

    - `id: string`

      Unique identifier for this event.

    - `result: "allow" or "deny"`

      UserToolConfirmationResult enum

      - `"allow"`

      - `"deny"`

    - `tool_use_id: string`

      The id of the `agent.tool_use` or `agent.mcp_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: "user.tool_confirmation"`

      - `"user.tool_confirmation"`

    - `deny_message: optional string`

      Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'.

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      When set, the confirmation routes to this subagent's thread rather than the primary. Echo this from the `session_thread_id` on the `agent.tool_use` or `agent.mcp_tool_use` event that prompted the approval.

  - `beta_managed_agents_user_custom_tool_result_event: object { id, custom_tool_use_id, type, 4 more }`

    Event sent by the client providing the result of a custom tool execution.

    - `id: string`

      Unique identifier for this event.

    - `custom_tool_use_id: string`

      The id of the `agent.custom_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: "user.custom_tool_result"`

      - `"user.custom_tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

        - `citations: object { enabled }`

          Citation settings for a search result.

          - `enabled: boolean`

            Whether citations are enabled for this search result.

        - `content: array of BetaManagedAgentsSearchResultContent`

          Array of text content blocks from the search result.

          - `text: string`

            The text content.

          - `type: "text"`

            - `"text"`

        - `source: string`

          The URL source of the search result.

        - `title: string`

          The title of the search result.

        - `type: "search_result"`

          - `"search_result"`

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      Routes this result to a subagent thread. Copy from the `agent.custom_tool_use` event's `session_thread_id`.

  - `beta_managed_agents_agent_custom_tool_use_event: object { id, input, name, 3 more }`

    Event emitted when the agent calls a custom tool. The session goes idle until the client sends a `user.custom_tool_result` event with the result.

    - `id: string`

      Unique identifier for this event.

    - `input: map[unknown]`

      Input parameters for the tool call.

    - `name: string`

      Name of the custom tool being called.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.custom_tool_use"`

      - `"agent.custom_tool_use"`

    - `session_thread_id: optional string`

      When set, this event was cross-posted from a subagent's thread to surface its custom tool use on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.custom_tool_result` event to route the result back.

  - `beta_managed_agents_agent_message_event: object { id, content, processed_at, type }`

    An agent response event in the session conversation.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock`

      Array of text blocks comprising the agent response.

      - `text: string`

        The text content.

      - `type: "text"`

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.message"`

      - `"agent.message"`

  - `beta_managed_agents_agent_thinking_event: object { id, processed_at, type }`

    Indicates the agent is making forward progress via extended thinking. A progress signal, not a content carrier.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.thinking"`

      - `"agent.thinking"`

  - `beta_managed_agents_agent_mcp_tool_use_event: object { id, input, mcp_server_name, 5 more }`

    Event emitted when the agent invokes a tool provided by an MCP server.

    - `id: string`

      Unique identifier for this event.

    - `input: map[unknown]`

      Input parameters for the tool call.

    - `mcp_server_name: string`

      Name of the MCP server providing the tool.

    - `name: string`

      Name of the MCP tool being used.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.mcp_tool_use"`

      - `"agent.mcp_tool_use"`

    - `evaluated_permission: optional "allow" or "ask" or "deny"`

      AgentEvaluatedPermission enum

      - `"allow"`

      - `"ask"`

      - `"deny"`

    - `session_thread_id: optional string`

      When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

  - `beta_managed_agents_agent_mcp_tool_result_event: object { id, mcp_tool_use_id, processed_at, 3 more }`

    Event representing the result of an MCP tool execution.

    - `id: string`

      Unique identifier for this event.

    - `mcp_tool_use_id: string`

      The id of the `agent.mcp_tool_use` event this result corresponds to.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.mcp_tool_result"`

      - `"agent.mcp_tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

  - `beta_managed_agents_agent_tool_use_event: object { id, input, name, 4 more }`

    Event emitted when the agent invokes a built-in agent tool.

    - `id: string`

      Unique identifier for this event.

    - `input: map[unknown]`

      Input parameters for the tool call.

    - `name: string`

      Name of the agent tool being used.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.tool_use"`

      - `"agent.tool_use"`

    - `evaluated_permission: optional "allow" or "ask" or "deny"`

      AgentEvaluatedPermission enum

      - `"allow"`

      - `"ask"`

      - `"deny"`

    - `session_thread_id: optional string`

      When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

  - `beta_managed_agents_agent_tool_result_event: object { id, processed_at, tool_use_id, 3 more }`

    Event representing the result of an agent tool execution.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `tool_use_id: string`

      The id of the `agent.tool_use` event this result corresponds to.

    - `type: "agent.tool_result"`

      - `"agent.tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

  - `beta_managed_agents_agent_thread_message_received_event: object { id, content, from_session_thread_id, 3 more }`

    Delivery event written to the target thread's input stream when an agent-to-agent message arrives.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

      Message content blocks.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

    - `from_session_thread_id: string`

      Public `sthr_` ID of the thread that sent the message.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.thread_message_received"`

      - `"agent.thread_message_received"`

    - `from_agent_name: optional string`

      Name of the callable agent this message came from. Absent when received from the primary agent.

  - `beta_managed_agents_agent_thread_message_sent_event: object { id, content, processed_at, 3 more }`

    Observability event emitted to the sender's output stream when an agent-to-agent message is sent.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock`

      Message content blocks.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `to_session_thread_id: string`

      Public `sthr_` ID of the thread the message was sent to.

    - `type: "agent.thread_message_sent"`

      - `"agent.thread_message_sent"`

    - `to_agent_name: optional string`

      Name of the callable agent this message was sent to. Absent when sent to the primary agent.

  - `beta_managed_agents_agent_thread_context_compacted_event: object { id, processed_at, type }`

    Indicates that context compaction (summarization) occurred during the session.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "agent.thread_context_compacted"`

      - `"agent.thread_context_compacted"`

  - `beta_managed_agents_session_error_event: object { id, error, processed_at, type }`

    An error event indicating a problem occurred during session execution.

    - `id: string`

      Unique identifier for this event.

    - `error: BetaManagedAgentsUnknownError or BetaManagedAgentsModelOverloadedError or BetaManagedAgentsModelRateLimitedError or 5 more`

      An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

      - `beta_managed_agents_unknown_error: object { message, retry_status, type }`

        An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `type: "retrying"`

              - `"retrying"`

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `type: "exhausted"`

              - `"exhausted"`

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

            - `type: "terminal"`

              - `"terminal"`

        - `type: "unknown_error"`

          - `"unknown_error"`

      - `beta_managed_agents_model_overloaded_error: object { message, retry_status, type }`

        The model is currently overloaded. Emitted after automatic retries are exhausted.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "model_overloaded_error"`

          - `"model_overloaded_error"`

      - `beta_managed_agents_model_rate_limited_error: object { message, retry_status, type }`

        The model request was rate-limited.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "model_rate_limited_error"`

          - `"model_rate_limited_error"`

      - `beta_managed_agents_model_request_failed_error: object { message, retry_status, type }`

        A model request failed for a reason other than overload or rate-limiting.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "model_request_failed_error"`

          - `"model_request_failed_error"`

      - `beta_managed_agents_mcp_connection_failed_error: object { mcp_server_name, message, retry_status, type }`

        Failed to connect to an MCP server.

        - `mcp_server_name: string`

          Name of the MCP server that failed to connect.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "mcp_connection_failed_error"`

          - `"mcp_connection_failed_error"`

      - `beta_managed_agents_mcp_authentication_failed_error: object { mcp_server_name, message, retry_status, type }`

        Authentication to an MCP server failed.

        - `mcp_server_name: string`

          Name of the MCP server that failed authentication.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "mcp_authentication_failed_error"`

          - `"mcp_authentication_failed_error"`

      - `beta_managed_agents_billing_error: object { message, retry_status, type }`

        The caller's organization or workspace cannot make model requests — out of credits or spend limit reached. Retrying with the same credentials will not succeed; the caller must resolve the billing state.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "billing_error"`

          - `"billing_error"`

      - `beta_managed_agents_credential_host_unreachable_error: object { credential_id, message, retry_status, 2 more }`

        An `environment_variable` credential's `auth.networking.allowed_hosts` includes a host the environment's network policy does not permit.

        - `credential_id: string`

          ID of the affected credential.

        - `message: string`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying or BetaManagedAgentsRetryStatusExhausted or BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `beta_managed_agents_retry_status_retrying: object { type }`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `beta_managed_agents_retry_status_exhausted: object { type }`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `beta_managed_agents_retry_status_terminal: object { type }`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: "credential_host_unreachable_error"`

          - `"credential_host_unreachable_error"`

        - `vault_id: string`

          ID of the vault containing the affected credential.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.error"`

      - `"session.error"`

  - `beta_managed_agents_session_status_rescheduled_event: object { id, processed_at, type }`

    Indicates the session is recovering from an error state and is rescheduled for execution.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.status_rescheduled"`

      - `"session.status_rescheduled"`

  - `beta_managed_agents_session_status_running_event: object { id, processed_at, type }`

    Indicates the session is actively running and the agent is working.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.status_running"`

      - `"session.status_running"`

  - `beta_managed_agents_session_status_idle_event: object { id, processed_at, stop_reason, type }`

    Indicates the agent has paused and is awaiting user input.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `stop_reason: BetaManagedAgentsSessionEndTurn or BetaManagedAgentsSessionRequiresAction or BetaManagedAgentsSessionRetriesExhausted`

      The agent completed its turn naturally and is ready for the next user message.

      - `beta_managed_agents_session_end_turn: object { type }`

        The agent completed its turn naturally and is ready for the next user message.

        - `type: "end_turn"`

          - `"end_turn"`

      - `beta_managed_agents_session_requires_action: object { event_ids, type }`

        The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

        - `event_ids: array of string`

          The ids of events the agent is blocked on. Resolving fewer than all re-emits `session.status_idle` with the remainder.

        - `type: "requires_action"`

          - `"requires_action"`

      - `beta_managed_agents_session_retries_exhausted: object { type }`

        The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

        - `type: "retries_exhausted"`

          - `"retries_exhausted"`

    - `type: "session.status_idle"`

      - `"session.status_idle"`

  - `beta_managed_agents_session_status_terminated_event: object { id, processed_at, type }`

    Indicates the session has terminated, either due to an error or completion.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.status_terminated"`

      - `"session.status_terminated"`

  - `beta_managed_agents_session_thread_created_event: object { id, agent_name, processed_at, 2 more }`

    Emitted when a subagent is spawned as a new thread. Written to the parent thread's output stream so clients observing the session see child creation.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the callable agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public `sthr_` ID of the newly created thread.

    - `type: "session.thread_created"`

      - `"session.thread_created"`

  - `beta_managed_agents_span_outcome_evaluation_start_event: object { id, iteration, outcome_id, 2 more }`

    Emitted when an outcome evaluation cycle begins.

    - `id: string`

      Unique identifier for this event.

    - `iteration: number`

      0-indexed revision cycle. 0 is the first evaluation; 1 is the re-evaluation after the first revision; etc.

    - `outcome_id: string`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.outcome_evaluation_start"`

      - `"span.outcome_evaluation_start"`

  - `beta_managed_agents_span_outcome_evaluation_end_event: object { id, explanation, iteration, 6 more }`

    Emitted when an outcome evaluation cycle completes. Carries the verdict and aggregate token usage. A verdict of `needs_revision` means another evaluation cycle follows; `satisfied`, `max_iterations_reached`, `failed`, or `interrupted` are terminal — no further evaluation cycles follow.

    - `id: string`

      Unique identifier for this event.

    - `explanation: string`

      Human-readable explanation of the verdict. For `needs_revision`, describes which criteria failed and why.

    - `iteration: number`

      0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

    - `outcome_evaluation_start_id: string`

      The id of the corresponding `span.outcome_evaluation_start` event.

    - `outcome_id: string`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `result: string`

      Evaluation verdict. 'satisfied': criteria met, session goes idle. 'needs_revision': criteria not met, another revision cycle follows. 'max_iterations_reached': evaluation budget exhausted with criteria still unmet — one final acknowledgment turn follows before the session goes idle, but no further evaluation runs. 'failed': grader determined the rubric does not apply to the deliverables. 'interrupted': user sent an interrupt while evaluation was in progress.

    - `type: "span.outcome_evaluation_end"`

      - `"span.outcome_evaluation_end"`

    - `usage: object { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }`

      Token usage for a single model request.

      - `cache_creation_input_tokens: number`

        Tokens used to create prompt cache in this request.

      - `cache_read_input_tokens: number`

        Tokens read from prompt cache in this request.

      - `input_tokens: number`

        Input tokens consumed by this request.

      - `output_tokens: number`

        Output tokens generated by this request.

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `"standard"`

        - `"fast"`

  - `beta_managed_agents_span_model_request_start_event: object { id, processed_at, type }`

    Emitted when a model request is initiated by the agent.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.model_request_start"`

      - `"span.model_request_start"`

  - `beta_managed_agents_span_model_request_end_event: object { id, is_error, model_request_start_id, 3 more }`

    Emitted when a model request completes.

    - `id: string`

      Unique identifier for this event.

    - `is_error: boolean`

      Whether the model request resulted in an error.

    - `model_request_start_id: string`

      The id of the corresponding `span.model_request_start` event.

    - `model_usage: object { cache_creation_input_tokens, cache_read_input_tokens, input_tokens, 2 more }`

      Token usage for a single model request.

      - `cache_creation_input_tokens: number`

        Tokens used to create prompt cache in this request.

      - `cache_read_input_tokens: number`

        Tokens read from prompt cache in this request.

      - `input_tokens: number`

        Input tokens consumed by this request.

      - `output_tokens: number`

        Output tokens generated by this request.

      - `speed: optional "standard" or "fast"`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.model_request_end"`

      - `"span.model_request_end"`

  - `beta_managed_agents_span_outcome_evaluation_ongoing_event: object { id, iteration, outcome_id, 2 more }`

    Periodic heartbeat emitted while an outcome evaluation cycle is in progress. Distinguishes 'evaluation is actively running' from 'evaluation is stuck' between the corresponding `span.outcome_evaluation_start` and `span.outcome_evaluation_end` events.

    - `id: string`

      Unique identifier for this event.

    - `iteration: number`

      0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

    - `outcome_id: string`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "span.outcome_evaluation_ongoing"`

      - `"span.outcome_evaluation_ongoing"`

  - `beta_managed_agents_user_define_outcome_event: object { id, description, max_iterations, 4 more }`

    Echo of a `user.define_outcome` input event. Carries the server-generated `outcome_id` that subsequent `span.outcome_evaluation_*` events reference.

    - `id: string`

      Unique identifier for this event.

    - `description: string`

      What the agent should produce. Copied from the input event.

    - `max_iterations: number`

      Evaluate-then-revise cycles before giving up. Default 3, max 20.

    - `outcome_id: string`

      Server-generated `outc_` ID for this outcome. Referenced by `span.outcome_evaluation_*` events and the session's `outcome_evaluations` list.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `rubric: BetaManagedAgentsFileRubric or BetaManagedAgentsTextRubric`

      Rubric for grading the quality of an outcome.

      - `beta_managed_agents_file_rubric: object { file_id, type }`

        Rubric referenced by a file uploaded via the Files API.

        - `file_id: string`

          ID of the rubric file.

        - `type: "file"`

          - `"file"`

      - `beta_managed_agents_text_rubric: object { content, type }`

        Rubric content provided inline as text.

        - `content: string`

          Rubric content. Plain text or markdown — the grader treats it as freeform text.

        - `type: "text"`

          - `"text"`

    - `type: "user.define_outcome"`

      - `"user.define_outcome"`

  - `beta_managed_agents_session_deleted_event: object { id, processed_at, type }`

    Emitted when a session has been deleted. Terminates any active event stream — no further events will be emitted for this session.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.deleted"`

      - `"session.deleted"`

  - `beta_managed_agents_session_thread_status_running_event: object { id, agent_name, processed_at, 2 more }`

    A session thread has begun executing. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that started running.

    - `type: "session.thread_status_running"`

      - `"session.thread_status_running"`

  - `beta_managed_agents_session_thread_status_idle_event: object { id, agent_name, processed_at, 3 more }`

    A session thread has yielded and is awaiting input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that went idle.

    - `stop_reason: BetaManagedAgentsSessionEndTurn or BetaManagedAgentsSessionRequiresAction or BetaManagedAgentsSessionRetriesExhausted`

      The agent completed its turn naturally and is ready for the next user message.

      - `beta_managed_agents_session_end_turn: object { type }`

        The agent completed its turn naturally and is ready for the next user message.

      - `beta_managed_agents_session_requires_action: object { event_ids, type }`

        The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

      - `beta_managed_agents_session_retries_exhausted: object { type }`

        The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

    - `type: "session.thread_status_idle"`

      - `"session.thread_status_idle"`

  - `beta_managed_agents_session_thread_status_terminated_event: object { id, agent_name, processed_at, 2 more }`

    A session thread has terminated and will accept no further input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that terminated.

    - `type: "session.thread_status_terminated"`

      - `"session.thread_status_terminated"`

  - `beta_managed_agents_user_tool_result_event: object { id, tool_use_id, type, 4 more }`

    Event sent by the client providing the result of an agent-toolset tool execution. Only valid on `self_hosted` environments, where sandbox-routed tools are executed by the client rather than the server.

    - `id: string`

      Unique identifier for this event.

    - `tool_use_id: string`

      The id of the `agent.tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: "user.tool_result"`

      - `"user.tool_result"`

    - `content: optional array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsSearchResultBlock`

      The result content returned by the tool.

      - `beta_managed_agents_text_block: object { text, type }`

        Regular text content.

      - `beta_managed_agents_image_block: object { source, type }`

        Image content specified directly as base64 data or as a reference via a URL.

      - `beta_managed_agents_document_block: object { source, type, context, title }`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `beta_managed_agents_search_result_block: object { citations, content, source, 2 more }`

        A block containing a web search result.

    - `is_error: optional boolean`

      Whether the tool execution resulted in an error.

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

    - `session_thread_id: optional string`

      Routes this result to a subagent thread. Copy from the `agent.tool_use` event's `session_thread_id`.

  - `beta_managed_agents_session_thread_status_rescheduled_event: object { id, agent_name, processed_at, 2 more }`

    A session thread hit a transient error and is retrying automatically. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: string`

      Unique identifier for this event.

    - `agent_name: string`

      Name of the agent the thread runs.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `session_thread_id: string`

      Public sthr_ ID of the thread that is retrying.

    - `type: "session.thread_status_rescheduled"`

      - `"session.thread_status_rescheduled"`

  - `beta_managed_agents_session_updated_event: object { id, processed_at, type, 3 more }`

    Emitted when an UpdateSession request changed at least one field. Carries only the fields that changed; absent fields were not part of the update. The new configuration applies from the next turn.

    - `id: string`

      Unique identifier for this event.

    - `processed_at: string`

      A timestamp in RFC 3339 format

    - `type: "session.updated"`

      - `"session.updated"`

    - `agent: optional object { id, description, mcp_servers, 8 more }`

      Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time.

      - `id: string`

      - `description: string`

      - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

        - `name: string`

        - `type: "url"`

          - `"url"`

        - `url: string`

      - `model: object { id, speed }`

        Model identifier and configuration.

        - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

          The model that will power your agent.

          See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

          - `"claude-fable-5"`

            Next generation of intelligence for the hardest knowledge work and coding problems

          - `"claude-opus-4-8"`

            Frontier intelligence for long-running agents and coding

          - `"claude-opus-4-7"`

            Frontier intelligence for long-running agents and coding

          - `"claude-opus-4-6"`

            Most intelligent model for building agents and coding

          - `"claude-sonnet-4-6"`

            Best combination of speed and intelligence

          - `"claude-haiku-4-5"`

            Fastest model with near-frontier intelligence

          - `"claude-haiku-4-5-20251001"`

            Fastest model with near-frontier intelligence

          - `"claude-opus-4-5"`

            Premium model combining maximum intelligence with practical performance

          - `"claude-opus-4-5-20251101"`

            Premium model combining maximum intelligence with practical performance

          - `"claude-sonnet-4-5"`

            High-performance model for agents and coding

          - `"claude-sonnet-4-5-20250929"`

            High-performance model for agents and coding

        - `speed: optional "standard" or "fast"`

          Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

          - `"standard"`

          - `"fast"`

      - `multiagent: object { agents, type }`

        Resolved coordinator topology with full agent definitions for each roster member.

        - `agents: array of BetaManagedAgentsSessionThreadAgent`

          Full `agent` definitions the coordinator may spawn as session threads.

          - `id: string`

          - `description: string`

          - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition`

            - `name: string`

            - `type: "url"`

            - `url: string`

          - `model: object { id, speed }`

            Model identifier and configuration.

            - `id: "claude-fable-5" or "claude-opus-4-8" or "claude-opus-4-7" or 8 more or string`

              The model that will power your agent.

              See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

            - `speed: optional "standard" or "fast"`

              Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

          - `name: string`

          - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

            - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

              A resolved Anthropic-managed skill.

              - `skill_id: string`

              - `type: "anthropic"`

                - `"anthropic"`

              - `version: string`

            - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

              A resolved user-created custom skill.

              - `skill_id: string`

              - `type: "custom"`

                - `"custom"`

              - `version: string`

          - `system: string`

          - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

            - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

              - `configs: array of BetaManagedAgentsAgentToolConfig`

                - `enabled: boolean`

                - `name: "bash" or "edit" or "read" or 5 more`

                  Built-in agent tool identifier.

                  - `"bash"`

                  - `"edit"`

                  - `"read"`

                  - `"write"`

                  - `"glob"`

                  - `"grep"`

                  - `"web_fetch"`

                  - `"web_search"`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                    - `type: "always_allow"`

                      - `"always_allow"`

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

                    - `type: "always_ask"`

                      - `"always_ask"`

              - `default_config: object { enabled, permission_policy }`

                Resolved default configuration for agent tools.

                - `enabled: boolean`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

              - `type: "agent_toolset_20260401"`

                - `"agent_toolset_20260401"`

            - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

              - `configs: array of BetaManagedAgentsMCPToolConfig`

                - `enabled: boolean`

                - `name: string`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

              - `default_config: object { enabled, permission_policy }`

                Resolved default configuration for all tools from an MCP server.

                - `enabled: boolean`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `beta_managed_agents_always_allow_policy: object { type }`

                    Tool calls are automatically approved without user confirmation.

                  - `beta_managed_agents_always_ask_policy: object { type }`

                    Tool calls require user confirmation before execution.

              - `mcp_server_name: string`

              - `type: "mcp_toolset"`

                - `"mcp_toolset"`

            - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

              A custom tool as returned in API responses.

              - `description: string`

              - `input_schema: object { type, properties, required }`

                JSON Schema for custom tool input parameters.

                - `type: "object"`

                - `properties: optional map[unknown]`

                - `required: optional array of string`

              - `name: string`

              - `type: "custom"`

                - `"custom"`

          - `type: "agent"`

            - `"agent"`

          - `version: number`

        - `type: "coordinator"`

          - `"coordinator"`

      - `name: string`

      - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill`

        - `beta_managed_agents_anthropic_skill: object { skill_id, type, version }`

          A resolved Anthropic-managed skill.

        - `beta_managed_agents_custom_skill: object { skill_id, type, version }`

          A resolved user-created custom skill.

      - `system: string`

      - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool`

        - `beta_managed_agents_agent_toolset20260401: object { configs, default_config, type }`

        - `beta_managed_agents_mcp_toolset: object { configs, default_config, mcp_server_name, type }`

        - `beta_managed_agents_custom_tool: object { description, input_schema, name, type }`

          A custom tool as returned in API responses.

      - `type: "agent"`

        - `"agent"`

      - `version: number`

    - `metadata: optional map[string]`

      The session's full metadata bag after the update. Present when the update set non-empty metadata; absent when metadata was unchanged or cleared to empty.

    - `title: optional string`

      The session's new title. Present only when the update changed it.

  - `beta_managed_agents_system_message_event: object { id, content, type, processed_at }`

    A mid-conversation system message event. Carries system-role content that is appended to the session as a `role: "system"` turn.

    - `id: string`

      Unique identifier for this event.

    - `content: array of BetaManagedAgentsSystemContentBlock`

      System content blocks. Text-only.

      - `text: string`

        The text content.

      - `type: "text"`

        - `"text"`

    - `type: "system.message"`

      - `"system.message"`

    - `processed_at: optional string`

      A timestamp in RFC 3339 format

### Example

```cli
ant beta:sessions:threads:events stream \
  --api-key my-anthropic-api-key \
  --session-id sesn_011CZkZAtmR3yMPDzynEDxu7 \
  --thread-id sthr_011CZkZVWa6oIjw0rgXZpnBt
```

#### Response

```json
{
  "id": "sevt_011CZkZGOp0iBcp4kaQSihUmy",
  "content": [
    {
      "text": "Where is my order #1234?",
      "type": "text"
    }
  ],
  "type": "user.message",
  "processed_at": "2026-03-15T10:00:00Z"
}
```