Claude Platform Docs

Create Session

client.beta.sessions.create(SessionCreateParamsparams, RequestOptionsoptions?): BetaManagedAgentsSession
POST/v1/sessions

Create Session

Parameters
params: SessionCreateParams { agent, environment_id, budget, 6 more }
agent: string | BetaManagedAgentsAgentParams { id, type, version } | BetaManagedAgentsAgentWithOverridesParams { id, type, mcp_servers, 5 more }

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.

One of the following:
string
BetaManagedAgentsAgentParams { 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.

minLength1
maxLength128
type: "agent"
version?: number

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

formatint32
BetaManagedAgentsAgentWithOverridesParams { id, type, mcp_servers, 5 more }

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.

environment_id: string

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

minLength1
maxLength128
budget?: BetaManagedAgentsBudgetLimit { max_list_cost, type }

Body param: A hard spend ceiling. The session stops issuing new model requests once the tracked list cost reaches max_list_cost.

max_list_cost: BetaMonetaryAmount { amount, currency }

A monetary amount in a specific currency.

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.

type: "limit"
initial_events?: Array<BetaManagedAgentsUserMessageEventParams { content, type } | BetaManagedAgentsUserDefineOutcomeEventParams { description, rubric, type, max_iterations }>

Body param: Initial events to send to the session at creation, processed in order. Supports user.message and user.define_outcome events. Maximum 50 events.

One of the following:
BetaManagedAgentsUserMessageEventParams { content, type }

Parameters for sending a user message to the session.

BetaManagedAgentsUserDefineOutcomeEventParams { description, rubric, type, max_iterations }

Parameters for defining an outcome the agent should work toward. The agent begins work on receipt.

metadata?: Record<string, string>

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

resources?: Array<BetaManagedAgentsGitHubRepositoryResourceParams { authorization_token, type, url, 2 more } | BetaManagedAgentsFileResourceParams { file_id, type, mount_path } | BetaManagedAgentsMemoryStoreResourceParam { memory_store_id, type, access, instructions }>

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

One of the following:
BetaManagedAgentsGitHubRepositoryResourceParams { authorization_token, type, url, 2 more }

Mount a GitHub repository into the session's container.

BetaManagedAgentsFileResourceParams { 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.

minLength1
maxLength128
type: "file"
mount_path?: string | null

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

minLength1
maxLength4096
BetaManagedAgentsMemoryStoreResourceParam { 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"
access?: "read_write" | "read_only" | null

Access mode for an attached memory store.

One of the following:
"read_write"
"read_only"
instructions?: string | 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.

maxLength4096
title?: string | null

Body param: Human-readable session title.

maxLength500
vault_ids?: Array<string>

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

betas?: Array<AnthropicBeta>

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

One of the following:
(string & {})
"message-batches-2024-09-24" | "prompt-caching-2024-07-31" | "computer-use-2024-10-22" | 38 more
"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"
"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"
Returns
BetaManagedAgentsSession { id, agent, archived_at, 14 more }

A Managed Agents session.

Create Session

import Anthropic from "@anthropic-ai/sdk";

const client = new Anthropic({
  apiKey: process.env["ANTHROPIC_API_KEY"] // This is the default and can be omitted
});

const betaManagedAgentsSession = await client.beta.sessions.create({
  agent: "agent_011CZkYpogX7uDKUyvBTophP",
  environment_id: "env_011CZkZ9X2dpNyB7HsEFoRfW"
});

console.log(betaManagedAgentsSession.id);
{
  "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-opus-5",
      "effort": {
        "type": "low"
      },
      "inference_geo": "inference_geo",
      "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-opus-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_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"
            },
            "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_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": {
    "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"
}
Returns Examples
{
  "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-opus-5",
      "effort": {
        "type": "low"
      },
      "inference_geo": "inference_geo",
      "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-opus-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_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"
            },
            "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_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": {
    "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"
}