--- title: Create Session url: https://platform.claude.com/docs/en/api/http/beta/sessions/create --- # Create Session **POST** `/v1/sessions` Create Session ## Headers - `"anthropic-version": optional string` The version of the Claude API you want to use. Read more about versioning and our version history [here](https://platform.claude.com/docs/en/api/versioning?sdk_languages=http). - `"anthropic-beta": optional array of AnthropicBeta` This endpoint is in beta: requests must send `managed-agents-2026-04-01` in this header. - `string` - `"message-batches-2024-09-24"` - `"prompt-caching-2024-07-31"` - `"computer-use-2024-10-22"` - `"computer-use-2025-01-24"` - `"pdfs-2024-09-25"` - `"token-counting-2024-11-01"` - `"token-efficient-tools-2025-02-19"` - `"output-128k-2025-02-19"` - `"files-api-2025-04-14"` - `"mcp-client-2025-04-04"` - `"mcp-client-2025-11-20"` - `"dev-full-thinking-2025-05-14"` - `"interleaved-thinking-2025-05-14"` - `"code-execution-2025-05-22"` - `"extended-cache-ttl-2025-04-11"` - `"context-1m-2025-08-07"` - `"context-management-2025-06-27"` - `"model-context-window-exceeded-2025-08-26"` - `"skills-2025-10-02"` - `"fast-mode-2026-02-01"` - `"output-300k-2026-03-24"` - `"user-profiles-2026-03-24"` - `"user-profiles-2026-08-18"` - `"user-profiles-2026-09-04"` - `"advisor-tool-2026-03-01"` - `"managed-agents-2026-04-01"` - `"cache-diagnosis-2026-04-07"` - `"dreaming-2026-04-21"` - `"thinking-token-count-2026-05-13"` - `"server-side-fallback-2026-06-01"` - `"server-side-fallback-2026-07-01"` - `"fallback-credit-2026-06-01"` - `"fallback-credit-2026-07-01"` - `"agent-memory-2026-07-22"` - `"mid-conversation-tool-changes-2026-07-01"` - `"compact-2026-01-12"` - `"computer-use-2025-11-24"` - `"mcp-tunnels-2026-06-22"` - `"structured-outputs-2025-11-13"` - `"task-budgets-2026-03-13"` - `"thinking-display-updates-2026-08-18"` - `"ce-user-management-2026-07-13"` - `"mid-conversation-output-config-2026-07-01"` - `"thinking-binding-controls-2026-08-01"` - `"mid-conversation-system-clear-at-2026-08-21"` - `"compact-2026-09-04"` - `"inline-tools-2026-09-15"` - `"mcp-client-2026-09-15"` - `"ce-plugins-2026-09-01"` - `"spend-limit-reads-2026-09-26"` - `"telemetry-destinations-2026-08-11"` - `"anthropic-workspace-id": optional string` Optional header to select the Workspace for this request. The value is a Workspace ID (for example, `wrkspc_011CZkZaBF1tNoB5wlCeusgy`). Only needed for credentials that can act on more than one Workspace. A credential that belongs to a specific Workspace may omit it; if sent, it must match that Workspace. ## Body parameters - `agent: string or BetaManagedAgentsAgentParams or BetaManagedAgentsAgentWithOverridesParams` 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. - `string` - `BetaManagedAgentsAgentParams object` Specification for an Agent. Provide a specific `version` or use the short-form `agent="agent_id"` for the most recent version - `type: "agent"` - `id: string` The `agent` ID. minLength: 1, maxLength: 128 - `version: optional number` The specific `agent` version to use. Omit to use the latest version. Must be at least 1 if specified. format: int32 - `BetaManagedAgentsAgentWithOverridesParams object` Reference to an `agent` plus optional configuration overrides. Each provided field replaces the agent's value for the caller's use; the agent resource is unchanged. - `type: "agent_with_overrides"` - `id: string` The `agent` ID. minLength: 1, maxLength: 128 - `mcp_servers: optional array of BetaManagedAgentsURLMCPServerParams` Replacement MCP server list. Full replacement: the provided array becomes the MCP servers. Send an empty array to clear; omit to preserve the agent's servers. - `type: "url"` - `name: string` Unique name for this server, referenced by mcp_toolset configurations. 1-255 characters. minLength: 1, maxLength: 255 - `url: string` Endpoint URL for the MCP server. maxLength: 2048 - `model: optional BetaManagedAgentsModel or BetaManagedAgentsModelConfigParams` Replacement model. Accepts the model string, e.g. `claude-opus-5-5`, or a `model_config` object. Omit to use the agent's model. - `BetaManagedAgentsModel = "claude-haiku-5-5" or "claude-sonnet-5-5" or "claude-opus-5-5" or 14 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-haiku-5-5"` Fastest model for high-volume, real-time tasks - `"claude-sonnet-5-5"` Efficient model for coding and agents - `"claude-opus-5-5"` Powerful intelligence for coding, knowledge work, and long-running agents - `"claude-fable-5-1"` Frontier intelligence for ambitious tasks across coding, scientific discovery, and enterprise workflows - `"claude-sonnet-5"` Efficient model for coding and agents - `"claude-fable-5"` Next generation of intelligence for the hardest knowledge work and coding problems - `"claude-opus-5"` Powerful intelligence for long-running agents and coding - `"claude-opus-4-8"` Powerful intelligence for long-running agents and coding - `"claude-opus-4-7"` Powerful intelligence for long-running agents and coding - `"claude-opus-4-6"` Powerful intelligence for long-running agents and coding - `"claude-sonnet-4-6"` Best combination of speed and intelligence - `"claude-haiku-4-5"` - `"claude-haiku-4-5-20251001"` - `"claude-opus-4-5"` Powerful intelligence for long-running agents and coding - `"claude-opus-4-5-20251101"` Powerful intelligence for long-running agents and coding - `"claude-sonnet-4-5"` **Deprecated**: Will reach end-of-life on November 30, 2026. Please migrate to claude-sonnet-5-5. Visit https://docs.anthropic.com/en/docs/resources/model-deprecations for more information. High-performance model for agents and coding - `"claude-sonnet-4-5-20250929"` **Deprecated**: Will reach end-of-life on November 30, 2026. Please migrate to claude-sonnet-5-5. Visit https://docs.anthropic.com/en/docs/resources/model-deprecations for more information. High-performance model for agents and coding - `string` - `BetaManagedAgentsModelConfigParams object` An object that defines additional configuration control over model use - `id: BetaManagedAgentsModel` The model that will power your agent. See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options. - `effort: optional "low" or "medium" or "high" or 2 more or BetaManagedAgentsEffortLow or BetaManagedAgentsEffortMedium or 3 more or null` How hard Claude works on each inference call. Accepts a bare level string (`"high"`) or `{"type": "high"}`. On create, omitting it resolves the per-model default; on update, omitting it leaves the stored value unchanged. - `"low"` Low effort. Favors latency over reasoning depth. - `"medium"` Medium effort. Balances latency and reasoning depth. - `"high"` High effort. Favors reasoning depth. - `"xhigh"` Extra-high effort. Not all models accept this level. - `"max"` Maximum effort. Favors reasoning depth over latency. - `BetaManagedAgentsEffortLow object` Low effort. Favors latency over reasoning depth. - `type: "low"` - `BetaManagedAgentsEffortMedium object` Medium effort. Balances latency and reasoning depth. - `type: "medium"` - `BetaManagedAgentsEffortHigh object` High effort. Favors reasoning depth. - `type: "high"` - `BetaManagedAgentsEffortXhigh object` Extra-high effort. Not all models accept this level. - `type: "xhigh"` - `BetaManagedAgentsEffortMax object` Maximum effort. Favors reasoning depth over latency. - `type: "max"` - `inference_geo: optional string or null` Geographic region for model inference. When unset, requests fall through to the workspace's default_inference_geo. On update, `model` is whole-object replacement — omitting inference_geo clears it. - `speed: optional "standard" or "fast" or null` Inference speed mode. Defaults to `standard`. - `"standard"` - `"fast"` - `skills: optional array of BetaManagedAgentsSkillParams` Replacement skill list. Full replacement: the provided array becomes the skills. Send an empty array to clear; omit to preserve the agent's skills. - `BetaManagedAgentsAnthropicSkillParams object` An Anthropic-managed skill. - `type: "anthropic"` - `skill_id: string` Identifier of the Anthropic skill (e.g., "xlsx"). minLength: 1, maxLength: 64 - `version: optional string or null` Version to pin. Defaults to latest if omitted. minLength: 1, maxLength: 64 - `BetaManagedAgentsCustomSkillParams object` A user-created custom skill. - `type: "custom"` - `skill_id: string` Tagged ID of the custom skill (e.g., "skill_01XJ5..."). minLength: 1, maxLength: 64 - `version: optional string or null` Version to pin. Defaults to latest if omitted. minLength: 1, maxLength: 64 - `system: optional string or null` Replacement system prompt. Up to 100,000 characters. Set to null to clear the agent's system prompt; omit to preserve it. maxLength: 100000 - `tools: optional array of BetaManagedAgentsAgentToolset20260401Params or BetaManagedAgentsMCPToolsetParams or BetaManagedAgentsCustomToolParams` Replacement tool list. Full replacement: the provided array becomes the tool configuration. Send an empty array to clear; omit to preserve the agent's tools. - `BetaManagedAgentsAgentToolset20260401Params object` Configuration for built-in agent tools. Use this to enable or disable groups of tools available to the agent. - `type: "agent_toolset_20260401"` - `configs: optional array of BetaManagedAgentsAgentToolConfigParams` Per-tool configuration overrides. - `BetaManagedAgentsBashToolConfigParams object` Configuration override for the bash tool. - `type: optional "bash"` - `name: "bash"` Must be "bash". - `enabled: optional boolean or null` Whether this tool is enabled and available to Claude. Overrides the default_config setting. - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null` Permission policy for this tool. Controls whether tool calls are auto-approved or require confirmation. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `type: "always_allow"` - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `type: "always_ask"` - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `type: "auto"` - `BetaManagedAgentsEditToolConfigParams object` Configuration override for the edit tool. - `type: optional "edit"` - `name: "edit"` Must be "edit". - `enabled: optional boolean or null` Whether this tool is enabled and available to Claude. Overrides the default_config setting. - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null` Permission policy for this tool. Controls whether tool calls are auto-approved or require confirmation. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `BetaManagedAgentsReadToolConfigParams object` Configuration override for the read tool. - `type: optional "read"` - `name: "read"` Must be "read". - `enabled: optional boolean or null` Whether this tool is enabled and available to Claude. Overrides the default_config setting. - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null` Permission policy for this tool. Controls whether tool calls are auto-approved or require confirmation. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `BetaManagedAgentsWriteToolConfigParams object` Configuration override for the write tool. - `type: optional "write"` - `name: "write"` Must be "write". - `enabled: optional boolean or null` Whether this tool is enabled and available to Claude. Overrides the default_config setting. - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null` Permission policy for this tool. Controls whether tool calls are auto-approved or require confirmation. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `BetaManagedAgentsGlobToolConfigParams object` Configuration override for the glob tool. - `type: optional "glob"` - `name: "glob"` Must be "glob". - `enabled: optional boolean or null` Whether this tool is enabled and available to Claude. Overrides the default_config setting. - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null` Permission policy for this tool. Controls whether tool calls are auto-approved or require confirmation. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `BetaManagedAgentsGrepToolConfigParams object` Configuration override for the grep tool. - `type: optional "grep"` - `name: "grep"` Must be "grep". - `enabled: optional boolean or null` Whether this tool is enabled and available to Claude. Overrides the default_config setting. - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null` Permission policy for this tool. Controls whether tool calls are auto-approved or require confirmation. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `BetaManagedAgentsWebFetchToolConfigParams object` Configuration override for the web_fetch tool. - `type: optional "web_fetch"` - `name: "web_fetch"` Must be "web_fetch". - `allowed_domains: optional array of string` Only fetch URLs whose host is one of these domains or a subdomain of one. Each entry is a plain hostname like "docs.example.com" (no scheme, port, or path). At most 64 entries; an empty list is rejected (omit the field instead). Cannot be combined with blocked_domains. - `blocked_domains: optional array of string` Never fetch URLs whose host is one of these domains or a subdomain of one. Each entry is a plain hostname like "ads.example.com" (no scheme, port, or path). At most 64 entries; an empty list is rejected (omit the field instead). Cannot be combined with allowed_domains. - `enabled: optional boolean or null` Whether this tool is enabled and available to Claude. Overrides the default_config setting. - `max_content_tokens: optional number or null` Maximum number of tokens of fetched text content to include in context per call. Does not apply to binary content such as PDFs. format: int32 - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null` Permission policy for this tool. Controls whether tool calls are auto-approved or require confirmation. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `url_sources: optional BetaManagedAgentsWebFetchURLSourcesParams or null` Which sources contribute URLs the tool may fetch. Omit to allow every source. - `client_tool_results: optional BetaManagedAgentsWebFetchURLSourceToolFilterParams or null` Which custom tools' results contribute URLs that may be fetched: "all" (the default), "none", or an only or except list. Each name in a list must be a custom tool in the same tools array. - `BetaManagedAgentsWebFetchURLSourceShorthand = "all" or "none"` String form of a url_sources value that has no field other than its type: "all" means {"type": "all"} and "none" means {"type": "none"}. - `"all"` - `"none"` - `BetaManagedAgentsWebFetchURLSourceToolFilter = BetaManagedAgentsWebFetchURLSourceAll or BetaManagedAgentsWebFetchURLSourceNone or BetaManagedAgentsWebFetchURLSourceOnly or BetaManagedAgentsWebFetchURLSourceExcept` Which tools' results contribute URLs that may be fetched. - `BetaManagedAgentsWebFetchURLSourceAll object` Every URL from this source may be fetched. This is the default. - `type: "all"` - `BetaManagedAgentsWebFetchURLSourceNone object` This source contributes no URLs that may be fetched. - `type: "none"` - `BetaManagedAgentsWebFetchURLSourceOnly object` Only the named tools' results contribute URLs that may be fetched. - `type: "only"` - `tools: array of BetaManagedAgentsWebFetchURLSourceToolReference` The tools whose results contribute. Between 1 and 128 entries, each with a different name. An empty list is rejected; use "none" to allow no tool's results. - `type: "tool_reference"` Must be "tool_reference". - `name: string` Name of the tool. Compared exactly, so upper and lower case letters are different. minLength: 1, maxLength: 128 - `BetaManagedAgentsWebFetchURLSourceExcept object` Every tool's results contribute URLs that may be fetched, except the named tools' results. - `type: "except"` - `tools: array of BetaManagedAgentsWebFetchURLSourceToolReference` The tools whose results do not contribute. Between 1 and 128 entries, each with a different name. An empty list is rejected; use "all" to leave out no tool's results. - `type: "tool_reference"` Must be "tool_reference". - `name: string` Name of the tool. Compared exactly, so upper and lower case letters are different. minLength: 1, maxLength: 128 - `server_tool_results: optional BetaManagedAgentsWebFetchURLSourceToolFilterParams or null` Which of the web_search and web_fetch tools' results contribute URLs that may be fetched: "all" (the default), "none", or an only or except list. Each name in a list must be "web_search" or "web_fetch". - `user_input: optional BetaManagedAgentsWebFetchURLSourceUserInputParams or null` Whether URLs in the text of user messages may be fetched: "all" (the default) or "none". - `BetaManagedAgentsWebFetchURLSourceShorthand = "all" or "none"` String form of a url_sources value that has no field other than its type: "all" means {"type": "all"} and "none" means {"type": "none"}. - `BetaManagedAgentsWebFetchURLSourceUserInput = BetaManagedAgentsWebFetchURLSourceAll or BetaManagedAgentsWebFetchURLSourceNone` Whether URLs in the text of user messages may be fetched. - `BetaManagedAgentsWebFetchURLSourceAll object` Every URL from this source may be fetched. This is the default. - `BetaManagedAgentsWebFetchURLSourceNone object` This source contributes no URLs that may be fetched. - `BetaManagedAgentsWebSearchToolConfigParams object` Configuration override for the web_search tool. - `type: optional "web_search"` - `name: "web_search"` Must be "web_search". - `allowed_domains: optional array of string` Only return search results whose host is one of these domains or a subdomain of one. Each entry is a plain hostname like "docs.example.com" (no scheme or port; an optional path suffix is accepted). At most 64 entries; an empty list is rejected (omit the field instead). Cannot be combined with blocked_domains. - `blocked_domains: optional array of string` Never return search results whose host is one of these domains or a subdomain of one. Each entry is a plain hostname like "ads.example.com" (no scheme or port; an optional path suffix is accepted). At most 64 entries; an empty list is rejected (omit the field instead). Cannot be combined with allowed_domains. - `enabled: optional boolean or null` Whether this tool is enabled and available to Claude. Overrides the default_config setting. - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null` Permission policy for this tool. Controls whether tool calls are auto-approved or require confirmation. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `user_location: optional BetaManagedAgentsUserLocation or null` Approximate user location for search result localization. - `type: "approximate"` Location precision. Only "approximate" is supported. - `city: optional string or null` City name. minLength: 1, maxLength: 255 - `country: optional string or null` Two-letter ISO 3166-1 country code, uppercase. - `region: optional string or null` Region or state name. minLength: 1, maxLength: 255 - `timezone: optional string or null` IANA timezone identifier, e.g. "America/Los_Angeles". minLength: 1, maxLength: 255 - `default_config: optional BetaManagedAgentsAgentToolsetDefaultConfigParams or null` Default configuration applied to all tools in this set. - `enabled: optional boolean or null` Whether tools are enabled and available to Claude by default. Defaults to true if not specified. - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null` Default permission policy for tools. Controls whether tool calls are auto-approved or require confirmation. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `BetaManagedAgentsMCPToolsetParams object` Configuration for tools from an MCP server defined in `mcp_servers`. - `type: "mcp_toolset"` - `mcp_server_name: string` Name of the MCP server. Must match a server name from the mcp_servers array. 1-255 characters. minLength: 1, maxLength: 255 - `configs: optional array of BetaManagedAgentsMCPToolConfigParams` Per-tool configuration overrides. - `name: string` Name of the MCP tool to configure. 1-128 characters. minLength: 1, maxLength: 128 - `enabled: optional boolean or null` Whether this tool is enabled. Overrides the `default_config` setting. - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null` Permission policy for this tool. Overrides the `default_config` setting. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `default_config: optional BetaManagedAgentsMCPToolsetDefaultConfigParams or null` Default configuration for all tools from this server. - `enabled: optional boolean or null` Whether tools are enabled by default. Defaults to true if not specified. - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null` Default permission policy for tools from this server. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `BetaManagedAgentsCustomToolParams object` 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. - `type: "custom"` - `description: string` Description of what the tool does, shown to the agent to help it decide when to use the tool. minLength: 1 - `input_schema: BetaManagedAgentsCustomToolInputSchema` JSON Schema defining the expected input parameters for the tool. - `type: "object"` - `properties: optional map[unknown] or null` - `required: optional array of string or null` - `name: string` Unique name for the tool. 1-128 characters; letters, digits, underscores, and hyphens. minLength: 1, maxLength: 128 - `version: optional number` The specific `agent` version to use. Omit to use the latest version. format: int32 - `environment_id: string` ID of the `environment` defining the container configuration for this session. minLength: 1, maxLength: 128 - `budget: optional BetaManagedAgentsBudgetLimit` Enforced spend ceiling for the session. Omit to create an uncapped session. Every model the session can run — the agent's model and each callable agent's model — must have a public list price, or the request is rejected with reason `model_not_budgetable`. - `type: "limit"` - `max_list_cost: BetaMonetaryAmount` Maximum list cost the session may accrue. List price is used regardless of any negotiated discount, so the cap fires at or before the actual charge. - `amount: string` Amount in minor units of the currency, as an integer decimal string with no leading zeros: "2500" is $25.00 and "50" is fifty cents. A string rather than a number so no float rounding is ever applied. - `currency: BetaCurrency` Uppercase ISO-4217 currency code. `USD` is the only currency currently supported; the accepted set is closed and grows only when a new currency is priced. - `initial_events: optional array of BetaManagedAgentsUserMessageEventParams or BetaManagedAgentsUserDefineOutcomeEventParams` Initial events to send to the `session` at creation, processed in order. Supports `user.message` and `user.define_outcome` events. Maximum 50 events. - `BetaManagedAgentsUserMessageEventParams object` Parameters for sending a user message to the session. - `type: "user.message"` - `content: array of BetaManagedAgentsTextBlock or BetaManagedAgentsImageBlock or BetaManagedAgentsDocumentBlock or BetaManagedAgentsRedactedBlock` Array of content blocks for the user message. - `BetaManagedAgentsTextBlock object` Regular text content. - `type: "text"` - `text: string` The text content. minLength: 1 - `BetaManagedAgentsImageBlock object` Image content specified directly as base64 data or as a reference via a URL. - `type: "image"` - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource` The source of the image data. - `BetaManagedAgentsBase64ImageSource object` Base64-encoded image data. - `type: "base64"` - `data: string` Base64-encoded image data. minLength: 1 - `media_type: string` MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp"). minLength: 1 - `BetaManagedAgentsURLImageSource object` Image referenced by URL. - `type: "url"` - `url: string` URL of the image to fetch. minLength: 1 - `BetaManagedAgentsFileImageSource object` Image referenced by file ID. - `type: "file"` - `file_id: string` ID of a previously uploaded file. minLength: 1 - `BetaManagedAgentsDocumentBlock object` Document content, either specified directly as base64 data, as text, or as a reference via a URL. - `type: "document"` - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource` The source of the document data. - `BetaManagedAgentsBase64DocumentSource object` Base64-encoded document data. - `type: "base64"` - `data: string` Base64-encoded document data. minLength: 1 - `media_type: string` MIME type of the document (e.g., "application/pdf"). minLength: 1 - `BetaManagedAgentsPlainTextDocumentSource object` Plain text document content. - `type: "text"` - `data: string` The plain text content. minLength: 1 - `media_type: "text/plain"` MIME type of the text content. Must be "text/plain". - `BetaManagedAgentsURLDocumentSource object` Document referenced by URL. - `type: "url"` - `url: string` URL of the document to fetch. minLength: 1 - `BetaManagedAgentsFileDocumentSource object` Document referenced by file ID. - `type: "file"` - `file_id: string` ID of a previously uploaded file. minLength: 1 - `context: optional string or null` Additional context about the document for the model. - `title: optional string or null` The title of the document. - `BetaManagedAgentsRedactedBlock object` Placeholder for content withheld by Anthropic model policy. - `type: "redacted"` - `BetaManagedAgentsUserDefineOutcomeEventParams object` Parameters for defining an outcome the agent should work toward. The agent begins work on receipt. - `type: "user.define_outcome"` - `description: string` What the agent should produce. This is the task specification. - `rubric: BetaManagedAgentsFileRubricParams or BetaManagedAgentsTextRubricParams` How to grade the outcome. Text or file reference. - `BetaManagedAgentsFileRubricParams object` Rubric referenced by a file uploaded via the Files API. - `type: "file"` - `file_id: string` ID of the rubric file. - `BetaManagedAgentsTextRubricParams object` Rubric content provided inline as text. - `type: "text"` - `content: string` Rubric content. Plain text or markdown — the grader treats it as freeform text. Maximum 262144 characters. maxLength: 262144 - `max_iterations: optional number or null` Eval→revision cycles before giving up. Default 3, max 20. format: int32 - `metadata: optional map[string]` Arbitrary key-value metadata attached to the session. Maximum 16 pairs, keys up to 64 chars, values up to 512 chars. - `resources: optional array of BetaManagedAgentsGitHubRepositoryResourceParams or BetaManagedAgentsFileResourceParams or BetaManagedAgentsMemoryStoreResourceParam` Resources (e.g. repositories, files) to mount into the session's container. - `BetaManagedAgentsGitHubRepositoryResourceParams object` Mount a GitHub repository into the session's container. - `type: "github_repository"` - `url: string` Github URL of the repository minLength: 1, maxLength: 2048 - `authorization_token: optional string` GitHub authorization token used to clone the repository. Required for private repositories; optional for public ones. minLength: 1, maxLength: 4096 - `checkout: optional BetaManagedAgentsBranchCheckout or BetaManagedAgentsCommitCheckout or null` Branch or commit to check out. Defaults to the repository's default branch. - `BetaManagedAgentsBranchCheckout object` - `type: "branch"` - `name: string` Branch name to check out. minLength: 1, maxLength: 255 - `BetaManagedAgentsCommitCheckout object` - `type: "commit"` - `sha: string` Full commit SHA to check out. minLength: 7, maxLength: 64 - `mount_path: optional string or null` Mount path in the container. Defaults to `/workspace/`. minLength: 1, maxLength: 4096 - `BetaManagedAgentsFileResourceParams object` Mount a file uploaded via the Files API into the session. - `type: "file"` - `file_id: string` ID of a previously uploaded file. minLength: 1, maxLength: 128 - `mount_path: optional string or null` Mount path in the container. Defaults to `/mnt/session/uploads/`. minLength: 1, maxLength: 4096 - `BetaManagedAgentsMemoryStoreResourceParam object` Parameters for attaching a memory store to an agent session. - `type: "memory_store"` - `memory_store_id: string` The memory store ID (memstore_...). Must belong to the caller's organization and workspace. - `access: optional "read_write" or "read_only" or null` Access mode for the mounted store. Defaults to read_write. read_only mounts the store as a read-only filesystem. - `"read_write"` - `"read_only"` - `instructions: optional string or null` Per-attachment guidance for the agent on how to use this store. Rendered into the memory section of the system prompt. Max 4096 chars. maxLength: 4096 - `title: optional string or null` Human-readable session title. maxLength: 500 - `vault_ids: optional array of string` Vault IDs for stored credentials the agent can use during the session. ## Returns - `BetaManagedAgentsSession object` A Managed Agents `session`. - `type: "session"` - `id: string` - `agent: BetaManagedAgentsSessionAgent` Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time. - `type: "agent"` - `id: string` - `description: string or null` - `execution_identity: BetaManagedAgentsExecutionIdentity` Execution principal snapshotted from the agent at session creation. Always present; `{"type": "service_account"}` when runs carry no customer-named principal. - `BetaManagedAgentsAWSRoleExecutionIdentity object` An AWS IAM role principal as returned in API responses. - `type: "aws_role"` - `role_arn: string` The IAM role's ARN. - `BetaManagedAgentsServiceAccountExecutionIdentity object` The Anthropic-managed service account as returned in API responses. - `type: "service_account"` - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition` - `type: "url"` - `name: string` - `url: string` - `model: BetaManagedAgentsModelConfig` Model identifier and configuration. - `id: BetaManagedAgentsModel` The model that will power your agent. See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options. - `"claude-haiku-5-5"` Fastest model for high-volume, real-time tasks - `"claude-sonnet-5-5"` Efficient model for coding and agents - `"claude-opus-5-5"` Powerful intelligence for coding, knowledge work, and long-running agents - `"claude-fable-5-1"` Frontier intelligence for ambitious tasks across coding, scientific discovery, and enterprise workflows - `"claude-sonnet-5"` Efficient model for coding and agents - `"claude-fable-5"` Next generation of intelligence for the hardest knowledge work and coding problems - `"claude-opus-5"` Powerful intelligence for long-running agents and coding - `"claude-opus-4-8"` Powerful intelligence for long-running agents and coding - `"claude-opus-4-7"` Powerful intelligence for long-running agents and coding - `"claude-opus-4-6"` Powerful intelligence for long-running agents and coding - `"claude-sonnet-4-6"` Best combination of speed and intelligence - `"claude-haiku-4-5"` - `"claude-haiku-4-5-20251001"` - `"claude-opus-4-5"` Powerful intelligence for long-running agents and coding - `"claude-opus-4-5-20251101"` Powerful intelligence for long-running agents and coding - `"claude-sonnet-4-5"` **Deprecated**: Will reach end-of-life on November 30, 2026. Please migrate to claude-sonnet-5-5. Visit https://docs.anthropic.com/en/docs/resources/model-deprecations for more information. High-performance model for agents and coding - `"claude-sonnet-4-5-20250929"` **Deprecated**: Will reach end-of-life on November 30, 2026. Please migrate to claude-sonnet-5-5. Visit https://docs.anthropic.com/en/docs/resources/model-deprecations for more information. High-performance model for agents and coding - `string` - `effort: optional BetaManagedAgentsEffortLow or BetaManagedAgentsEffortMedium or BetaManagedAgentsEffortHigh or 2 more` How hard Claude works on each inference call. One of `low`, `medium`, `high`, `xhigh`, `max`. Always present; resolved to the per-model default at save time when not supplied. - `BetaManagedAgentsEffortLow object` Low effort. Favors latency over reasoning depth. - `type: "low"` - `BetaManagedAgentsEffortMedium object` Medium effort. Balances latency and reasoning depth. - `type: "medium"` - `BetaManagedAgentsEffortHigh object` High effort. Favors reasoning depth. - `type: "high"` - `BetaManagedAgentsEffortXhigh object` Extra-high effort. Not all models accept this level. - `type: "xhigh"` - `BetaManagedAgentsEffortMax object` Maximum effort. Favors reasoning depth over latency. - `type: "max"` - `inference_geo: optional string` Geographic region for model inference. When unset, requests fall through to the workspace's default_inference_geo. - `speed: optional "standard" or "fast"` Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Defaults to `standard`. Not all models support `fast`; invalid combinations are rejected at create time. - `"standard"` - `"fast"` - `multiagent: BetaManagedAgentsSessionMultiagent or null` Resolved multiagent orchestration configuration. Null when the agent is single-threaded. - `BetaManagedAgentsSessionMultiagentCoordinator object` Resolved coordinator topology with full agent definitions for each roster member. - `type: "coordinator"` - `agents: array of BetaManagedAgentsSessionThreadAgent or BetaManagedAgentsAdvisor` Full `agent` definitions the coordinator may spawn as session threads. - `BetaManagedAgentsSessionThreadAgent object` 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`. - `type: "agent"` - `id: string` - `description: string or null` - `execution_identity: BetaManagedAgentsExecutionIdentity` Execution principal snapshotted from the agent at session creation. Always present; `{"type": "service_account"}` when runs carry no customer-named principal. - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition` - `type: "url"` - `name: string` - `url: string` - `model: BetaManagedAgentsModelConfig` Model identifier and configuration. - `name: string` - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill` - `BetaManagedAgentsAnthropicSkill object` A resolved Anthropic-managed skill. - `type: "anthropic"` - `skill_id: string` - `version: string` - `BetaManagedAgentsCustomSkill object` A resolved user-created custom skill. - `type: "custom"` - `skill_id: string` - `version: string` - `system: string or null` - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool` - `BetaManagedAgentsAgentToolset20260401 object` - `type: "agent_toolset_20260401"` - `configs: array of BetaManagedAgentsAgentToolConfig` - `BetaManagedAgentsBashToolConfig object` Configuration for the bash tool. - `type: "bash"` - `enabled: boolean` - `name: "bash"` - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy` Permission policy for tool execution. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `type: "always_allow"` - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `type: "always_ask"` - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `type: "auto"` - `BetaManagedAgentsEditToolConfig object` Configuration for the edit tool. - `type: "edit"` - `enabled: boolean` - `name: "edit"` - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy` Permission policy for tool execution. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `BetaManagedAgentsReadToolConfig object` Configuration for the read tool. - `type: "read"` - `enabled: boolean` - `name: "read"` - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy` Permission policy for tool execution. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `BetaManagedAgentsWriteToolConfig object` Configuration for the write tool. - `type: "write"` - `enabled: boolean` - `name: "write"` - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy` Permission policy for tool execution. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `BetaManagedAgentsGlobToolConfig object` Configuration for the glob tool. - `type: "glob"` - `enabled: boolean` - `name: "glob"` - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy` Permission policy for tool execution. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `BetaManagedAgentsGrepToolConfig object` Configuration for the grep tool. - `type: "grep"` - `enabled: boolean` - `name: "grep"` - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy` Permission policy for tool execution. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `BetaManagedAgentsWebFetchToolConfig object` Configuration for the web_fetch tool. - `type: "web_fetch"` - `enabled: boolean` - `name: "web_fetch"` - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy` Permission policy for tool execution. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `url_sources: BetaManagedAgentsWebFetchURLSources or null` Which sources contribute URLs the tool may fetch, always in the object form. Null when not set, which allows every source. - `client_tool_results: BetaManagedAgentsWebFetchURLSourceToolFilter or null` Which custom tools' results contribute URLs that may be fetched. Null when not set, which allows every custom tool's results. - `BetaManagedAgentsWebFetchURLSourceAll object` Every URL from this source may be fetched. This is the default. - `type: "all"` - `BetaManagedAgentsWebFetchURLSourceNone object` This source contributes no URLs that may be fetched. - `type: "none"` - `BetaManagedAgentsWebFetchURLSourceOnly object` Only the named tools' results contribute URLs that may be fetched. - `type: "only"` - `tools: array of BetaManagedAgentsWebFetchURLSourceToolReference` The tools whose results contribute. Between 1 and 128 entries, each with a different name. An empty list is rejected; use "none" to allow no tool's results. - `type: "tool_reference"` Must be "tool_reference". - `name: string` Name of the tool. Compared exactly, so upper and lower case letters are different. minLength: 1, maxLength: 128 - `BetaManagedAgentsWebFetchURLSourceExcept object` Every tool's results contribute URLs that may be fetched, except the named tools' results. - `type: "except"` - `tools: array of BetaManagedAgentsWebFetchURLSourceToolReference` The tools whose results do not contribute. Between 1 and 128 entries, each with a different name. An empty list is rejected; use "all" to leave out no tool's results. - `type: "tool_reference"` Must be "tool_reference". - `name: string` Name of the tool. Compared exactly, so upper and lower case letters are different. minLength: 1, maxLength: 128 - `server_tool_results: BetaManagedAgentsWebFetchURLSourceToolFilter or null` Which of the web_search and web_fetch tools' results contribute URLs that may be fetched. Null when not set, which allows both. - `user_input: BetaManagedAgentsWebFetchURLSourceUserInput or null` Whether URLs in the text of user messages may be fetched. Null when not set, which allows them. - `BetaManagedAgentsWebFetchURLSourceAll object` Every URL from this source may be fetched. This is the default. - `BetaManagedAgentsWebFetchURLSourceNone object` This source contributes no URLs that may be fetched. - `allowed_domains: optional array of string` - `blocked_domains: optional array of string` - `max_content_tokens: optional number or null` format: int32 - `BetaManagedAgentsWebSearchToolConfig object` Configuration for the web_search tool. - `type: "web_search"` - `enabled: boolean` - `name: "web_search"` - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy` Permission policy for tool execution. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `allowed_domains: optional array of string` - `blocked_domains: optional array of string` - `user_location: optional BetaManagedAgentsUserLocation or null` Approximate user location for search result localization. - `type: "approximate"` Location precision. Only "approximate" is supported. - `city: optional string or null` City name. minLength: 1, maxLength: 255 - `country: optional string or null` Two-letter ISO 3166-1 country code, uppercase. - `region: optional string or null` Region or state name. minLength: 1, maxLength: 255 - `timezone: optional string or null` IANA timezone identifier, e.g. "America/Los_Angeles". minLength: 1, maxLength: 255 - `default_config: BetaManagedAgentsAgentToolsetDefaultConfig` Resolved default configuration for agent tools. - `enabled: boolean` - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy` Permission policy for tool execution. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `BetaManagedAgentsMCPToolset object` - `type: "mcp_toolset"` - `configs: array of BetaManagedAgentsMCPToolConfig` - `enabled: boolean` - `name: string` - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy` Permission policy for tool execution. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `default_config: BetaManagedAgentsMCPToolsetDefaultConfig` Resolved default configuration for all tools from an MCP server. - `enabled: boolean` - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy` Permission policy for tool execution. - `BetaManagedAgentsAlwaysAllowPolicy object` Tool calls are automatically approved without user confirmation. - `BetaManagedAgentsAlwaysAskPolicy object` Tool calls require user confirmation before execution. - `BetaManagedAgentsAutoPolicy object` The server decides each tool call individually: it judges, from the tool, its input, and the session content so far, whether the call is safe to execute or high-risk, and evaluates it to allow when judged safe and to deny when judged high-risk. A call the server cannot reach a judgement on evaluates to ask. - `mcp_server_name: string` - `BetaManagedAgentsCustomTool object` A custom tool as returned in API responses. - `type: "custom"` - `description: string` - `input_schema: BetaManagedAgentsCustomToolInputSchema` JSON Schema for custom tool input parameters. - `type: "object"` - `properties: optional map[unknown] or null` - `required: optional array of string or null` - `name: string` - `version: number` format: int32 - `BetaManagedAgentsAdvisor object` Platform advisor roster entry: a model the session's primary thread may consult mid-turn. - `type: "advisor"` - `model: string` The advisor model id. - `BetaManagedAgentsSessionMultiagent20261001 object` Resolved multiagent configuration with three members, as copied to the `session` at creation. - `type: "multiagent_20261001"` - `advisor: BetaManagedAgentsMultiagentAdvisor` Whether the session's primary thread can consult an advisor model. - `BetaManagedAgentsMultiagentAdvisorEnabled object` The session's primary thread can consult `model` mid-turn. - `type: "enabled"` - `model: string` The advisor model id. - `BetaManagedAgentsMultiagentAdvisorDisabled object` The agent has no advisor. - `type: "disabled"` - `subagents: BetaManagedAgentsSessionMultiagentSubagents` Whether the agent can spawn session threads. - `BetaManagedAgentsSessionMultiagentSubagentsEnabled object` The agent can spawn session threads. - `type: "enabled"` - `inline_agents: BetaManagedAgentsMultiagentInlineAgents` Whether the agent can define inline agents, which are not saved, when it spawns session threads. - `BetaManagedAgentsMultiagentInlineAgentsEnabled object` The agent can define inline agents. - `type: "enabled"` - `BetaManagedAgentsMultiagentInlineAgentsDisabled object` The agent cannot define inline agents. - `type: "disabled"` - `predefined_agents: array of BetaManagedAgentsSessionThreadAgent` Full `agent` definitions of the predefined agents, which are saved agents that this agent can spawn as session threads. - `type: "agent"` - `id: string` - `description: string or null` - `execution_identity: BetaManagedAgentsExecutionIdentity` Execution principal snapshotted from the agent at session creation. Always present; `{"type": "service_account"}` when runs carry no customer-named principal. - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition` - `model: BetaManagedAgentsModelConfig` Model identifier and configuration. - `name: string` - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill` - `system: string or null` - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool` - `version: number` format: int32 - `BetaManagedAgentsMultiagentSubagentsDisabled object` The agent cannot spawn session threads. - `type: "disabled"` - `workflows: BetaManagedAgentsSessionMultiagentWorkflows` Whether the agent can start workflow runs. - `BetaManagedAgentsSessionMultiagentWorkflowsEnabled object` The agent can start workflow runs. - `type: "enabled"` - `inline_agents: BetaManagedAgentsMultiagentInlineAgents` Whether a run's plan can define inline agents, which are not saved. - `predefined_agents: array of BetaManagedAgentsSessionThreadAgent` Full `agent` definitions of the predefined agents, which are saved agents that a run's plan can use. - `type: "agent"` - `id: string` - `description: string or null` - `execution_identity: BetaManagedAgentsExecutionIdentity` Execution principal snapshotted from the agent at session creation. Always present; `{"type": "service_account"}` when runs carry no customer-named principal. - `mcp_servers: array of BetaManagedAgentsMCPServerURLDefinition` - `model: BetaManagedAgentsModelConfig` Model identifier and configuration. - `name: string` - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill` - `system: string or null` - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool` - `version: number` format: int32 - `BetaManagedAgentsMultiagentWorkflowsDisabled object` The agent cannot start workflow runs. - `type: "disabled"` - `name: string` - `skills: array of BetaManagedAgentsAnthropicSkill or BetaManagedAgentsCustomSkill` - `BetaManagedAgentsAnthropicSkill object` A resolved Anthropic-managed skill. - `BetaManagedAgentsCustomSkill object` A resolved user-created custom skill. - `system: string or null` - `tools: array of BetaManagedAgentsAgentToolset20260401 or BetaManagedAgentsMCPToolset or BetaManagedAgentsCustomTool` - `BetaManagedAgentsAgentToolset20260401 object` - `BetaManagedAgentsMCPToolset object` - `BetaManagedAgentsCustomTool object` A custom tool as returned in API responses. - `version: number` format: int32 - `archived_at: string or null` When the session was archived. Null if not archived. format: date-time - `budget: BetaManagedAgentsBudgetLimit or null` The session's enforced spend ceiling, or null when no budget is set. - `type: "limit"` - `max_list_cost: BetaMonetaryAmount` Maximum list cost the session may accrue. List price is used regardless of any negotiated discount, so the cap fires at or before the actual charge. - `amount: string` Amount in minor units of the currency, as an integer decimal string with no leading zeros: "2500" is $25.00 and "50" is fifty cents. A string rather than a number so no float rounding is ever applied. - `currency: BetaCurrency` Uppercase ISO-4217 currency code. `USD` is the only currency currently supported; the accepted set is closed and grows only when a new currency is priced. - `created_at: string` A timestamp in RFC 3339 format format: date-time - `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. - `type: "outcome_evaluation"` - `completed_at: string or null` When the outcome reached a terminal result. Null while `pending`/`running`/`evaluating`. format: date-time - `description: string` What the agent should produce. - `explanation: string or null` 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. format: int32 - `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. - `resources: array of BetaManagedAgentsSessionResource` - `BetaManagedAgentsGitHubRepositoryResource object` - `type: "github_repository"` - `id: string` - `created_at: string` A timestamp in RFC 3339 format format: date-time - `mount_path: string` - `updated_at: string` A timestamp in RFC 3339 format format: date-time - `url: string` - `checkout: optional BetaManagedAgentsBranchCheckout or BetaManagedAgentsCommitCheckout or null` - `BetaManagedAgentsBranchCheckout object` - `type: "branch"` - `name: string` Branch name to check out. minLength: 1, maxLength: 255 - `BetaManagedAgentsCommitCheckout object` - `type: "commit"` - `sha: string` Full commit SHA to check out. minLength: 7, maxLength: 64 - `BetaManagedAgentsFileResource object` - `type: "file"` - `id: string` - `created_at: string` A timestamp in RFC 3339 format format: date-time - `file_id: string` - `mount_path: string` - `updated_at: string` A timestamp in RFC 3339 format format: date-time - `BetaManagedAgentsMemoryStoreResource object` A memory store attached to an agent session. - `type: "memory_store"` - `memory_store_id: string` The memory store ID (memstore_...). Must belong to the caller's organization and workspace. - `access: optional "read_write" or "read_only" or null` Access mode for the mounted store. Defaults to `read_write`. `read_only` mounts the store as a read-only filesystem. - `"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 or null` Per-attachment guidance for the agent on how to use this store. Rendered into the memory section of the system prompt. Max 4096 chars. maxLength: 4096 - `mount_path: optional string or null` 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 or null` Display name of the memory store, snapshotted at attach time. Later edits to the store's name do not propagate to this resource. - `stats: BetaManagedAgentsSessionStats` Timing statistics for the session. - `active_seconds: optional number` Cumulative time in seconds the session spent in `running` status. Excludes idle time. format: double - `duration_seconds: optional number` Elapsed time since session creation in seconds. For terminated sessions, frozen at the final update. format: double - `status: "rescheduling" or "running" or "idle" or "terminated"` - `"rescheduling"` Transient error occurred, retrying automatically. - `"running"` Agent is actively executing. - `"idle"` Agent is waiting for input, including user messages or tool confirmations. Sessions start in idle. - `"terminated"` Session has ended, either due to an error or completion. - `title: string or null` - `updated_at: string` A timestamp in RFC 3339 format format: date-time - `usage: BetaManagedAgentsSessionUsage` Cumulative token usage for the session. - `active_seconds: optional number` Cumulative time in seconds during which the session had at least one thread in running status. Overlapping activity from concurrent threads is counted once, unlike `stats.active_seconds`, which sums each thread's own active time. This is the duration the session's runtime cost is priced on. format: double - `cache_creation: optional BetaManagedAgentsCacheCreationUsage` Tokens used to create prompt cache entries, broken down by cache TTL. - `ephemeral_1h_input_tokens: optional number` Tokens used to create 1-hour ephemeral cache entries. format: int32 - `ephemeral_5m_input_tokens: optional number` Tokens used to create 5-minute ephemeral cache entries. format: int32 - `cache_read_input_tokens: optional number` Total tokens read from prompt cache. format: int32 - `input_tokens: optional number` Total input tokens consumed across all turns. format: int32 - `list_cost: optional BetaMonetaryAmount or null` Cumulative list cost of the session across all turns, priced at public list rates. Absent until cost tracking is available for the session. - `output_tokens: optional number` Total output tokens generated across all turns. format: int32 - `server_tool_use: optional BetaManagedAgentsServerToolUsage or null` Cumulative server-executed tool usage across all turns. Absent until server-tool tracking is available for the session. - `web_fetch_requests: optional number` Number of server-executed web fetch requests. format: int32 - `web_search_requests: optional number` Number of server-executed web search requests. format: int32 - `vault_ids: array of string` Vault IDs attached to the session at creation. Empty when no vaults were supplied. - `deployment_id: optional string or null` Deployment ID when the session was created from a deployment reference. Null otherwise. ## Example ```bash curl https://api.anthropic.com/v1/sessions \ -H 'Content-Type: application/json' \ -H 'anthropic-version: 2023-06-01' \ -H 'anthropic-beta: managed-agents-2026-04-01' \ -H "X-Api-Key: $ANTHROPIC_API_KEY" \ -d '{ "agent": "agent_011CZkYpogX7uDKUyvBTophP", "environment_id": "env_011CZkZ9X2dpNyB7HsEFoRfW", "initial_events": [ { "content": [ { "text": "Where is my order #1234?", "type": "text" } ], "type": "user.message" } ], "title": "Order #1234 inquiry" }' ``` ### Response (200) ```json { "id": "sesn_011CZkZAtmR3yMPDzynEDxu7", "agent": { "id": "agent_011CZkYpogX7uDKUyvBTophP", "description": "A general-purpose starter agent.", "execution_identity": { "type": "service_account" }, "mcp_servers": [ { "name": "example-mcp", "type": "url", "url": "https://example-server.modelcontextprotocol.io/sse" } ], "model": { "id": "claude-opus-5-5", "effort": { "type": "low" }, "inference_geo": "inference_geo", "speed": "standard" }, "multiagent": { "agents": [ { "id": "agent_011CZkYqphY8vELVzwCUpqiQ", "description": "A focused research subagent.", "execution_identity": { "type": "service_account" }, "mcp_servers": [ { "name": "example-mcp", "type": "url", "url": "https://example-server.modelcontextprotocol.io/sse" } ], "model": { "id": "claude-opus-5-5", "effort": { "type": "low" }, "inference_geo": "inference_geo", "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" }, "type": "bash" } ], "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_011CZkZFNu9hAbo3jZPRgTmx", "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" }, "type": "bash" } ], "default_config": { "enabled": true, "permission_policy": { "type": "always_ask" } }, "type": "agent_toolset_20260401" } ], "type": "agent", "version": 1 }, "archived_at": null, "budget": { "max_list_cost": { "amount": "2500", "currency": "USD" }, "type": "limit" }, "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_011CZkZRSw2kEfs6ncTVmjxP", "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_011CZkZCKr6eXym1gWMPdQiu", "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": { "active_seconds": 0, "cache_creation": { "ephemeral_1h_input_tokens": 0, "ephemeral_5m_input_tokens": 0 }, "cache_read_input_tokens": 0, "input_tokens": 0, "list_cost": { "amount": "2500", "currency": "USD" }, "output_tokens": 0, "server_tool_use": { "web_fetch_requests": 0, "web_search_requests": 3 } }, "vault_ids": [ "vlt_011CZkZDLs7fYzm1hXNPeRjv" ], "deployment_id": "deployment_id" } ```