Get Session Thread

get /v1/sessions/{session_id}/threads/{thread_id}

Get Session Thread

Path Parameters

• session_id: string

• thread_id: string

Header Parameters

• "anthropic-beta": optional array of AnthropicBeta

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

  • string

  • "message-batches-2024-09-24" or "prompt-caching-2024-07-31" or "computer-use-2024-10-22" or 22 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"

    • "advisor-tool-2026-03-01"

    • "managed-agents-2026-04-01"

    • "cache-diagnosis-2026-04-07"

Returns

• BetaManagedAgentsSessionThread 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: BetaManagedAgentsSessionThreadAgent

    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: BetaManagedAgentsModelConfig

      Model identifier and configuration.

      • id: BetaManagedAgentsModel

        The model that will power your agent.

        See models for additional details and options.

        • "claude-opus-4-7" or "claude-opus-4-6" or "claude-sonnet-4-6" or 6 more

          The model that will power your agent.

          See models for additional details and options.

          • "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

        • string

      • 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

      • BetaManagedAgentsAnthropicSkill object { skill_id, type, version }

        A resolved Anthropic-managed skill.

        • skill_id: string

        • type: "anthropic"

          • "anthropic"

        • version: string

      • BetaManagedAgentsCustomSkill 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

      • BetaManagedAgentsAgentToolset20260401 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.

            • BetaManagedAgentsAlwaysAllowPolicy object { type }

              Tool calls are automatically approved without user confirmation.

              • type: "always_allow"

                • "always_allow"

            • BetaManagedAgentsAlwaysAskPolicy object { type }

              Tool calls require user confirmation before execution.

              • type: "always_ask"

                • "always_ask"

        • default_config: BetaManagedAgentsAgentToolsetDefaultConfig

          Resolved default configuration for agent tools.

          • enabled: boolean

          • permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy

            Permission policy for tool execution.

            • BetaManagedAgentsAlwaysAllowPolicy object { type }

              Tool calls are automatically approved without user confirmation.

            • BetaManagedAgentsAlwaysAskPolicy object { type }

              Tool calls require user confirmation before execution.

        • type: "agent_toolset_20260401"

          • "agent_toolset_20260401"

      • BetaManagedAgentsMCPToolset 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.

            • BetaManagedAgentsAlwaysAllowPolicy object { type }

              Tool calls are automatically approved without user confirmation.

            • BetaManagedAgentsAlwaysAskPolicy object { type }

              Tool calls require user confirmation before execution.

        • default_config: BetaManagedAgentsMCPToolsetDefaultConfig

          Resolved default configuration for all tools from an MCP server.

          • enabled: boolean

          • permission_policy: BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy

            Permission policy for tool execution.

            • BetaManagedAgentsAlwaysAllowPolicy object { type }

              Tool calls are automatically approved without user confirmation.

            • BetaManagedAgentsAlwaysAskPolicy object { type }

              Tool calls require user confirmation before execution.

        • mcp_server_name: string

        • type: "mcp_toolset"

          • "mcp_toolset"

      • BetaManagedAgentsCustomTool object { description, input_schema, name, type }

        A custom tool as returned in API responses.

        • description: string

        • input_schema: BetaManagedAgentsCustomToolInputSchema

          JSON Schema for custom tool input parameters.

          • properties: optional map[unknown]

            JSON Schema properties defining the tool's input parameters.

          • required: optional array of string

            List of required property names.

          • type: optional "object"

            Must be 'object' for tool input schemas.

            • "object"

        • 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: BetaManagedAgentsSessionThreadStats

    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: BetaManagedAgentsSessionThreadStatus

    SessionThreadStatus enum

    • "running"

    • "idle"

    • "rescheduling"

    • "terminated"

  • type: "session_thread"

    • "session_thread"

  • updated_at: string

    A timestamp in RFC 3339 format

  • usage: BetaManagedAgentsSessionThreadUsage

    Cumulative token usage for a session thread across all turns.

    • cache_creation: optional BetaManagedAgentsCacheCreationUsage

      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

curl https://api.anthropic.com/v1/sessions/$SESSION_ID/threads/$THREAD_ID \
    -H 'anthropic-version: 2023-06-01' \
    -H 'anthropic-beta: managed-agents-2026-04-01' \
    -H "X-Api-Key: $ANTHROPIC_API_KEY"

Response

{
  "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
  }
}