Claude Platform Docs

List Session Threads

GET/v1/sessions/{session_id}/threads

List Session Threads

Path parameters
session_id: string
Query parameters
limit: optional number

Maximum results per page. Defaults to 1000.

formatint32
page: optional string

Opaque pagination cursor from a previous response's next_page. Forward-only.

Headers
"anthropic-beta": optional array of AnthropicBeta

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

One of the following:
string
"message-batches-2024-09-24" or "prompt-caching-2024-07-31" or "computer-use-2024-10-22" or 31 more
One of the following:
"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"
Returns
data: optional array of BetaManagedAgentsSessionThread { id, agent, archived_at, 8 more }

Threads in the session, primary first then children in spawn order.

id: string

Unique identifier for this thread.

agent: BetaManagedAgentsSessionThreadAgent { id, description, mcp_servers, 7 more } or BetaManagedAgentsAdvisor { model, type }

A session-resolved multiagent roster entry.

One of the following:
BetaManagedAgentsSessionThreadAgent object{ id, description, mcp_servers, 7 more }

Resolved agent definition for a single session_thread. Snapshot of the agent at thread creation time. The multiagent roster is not repeated here; read it from Session.agent.

BetaManagedAgentsAdvisor object{ model, type }

Platform advisor roster entry: a model the session's primary thread may consult mid-turn.

model: string

The advisor model id.

type: "advisor"
archived_at: string or null

A timestamp in RFC 3339 format

formatdate-time
created_at: string

A timestamp in RFC 3339 format

formatdate-time
parent_thread_id: string or null

Parent thread that spawned this thread. Null for the primary thread.

session_id: string

The session this thread belongs to.

stats: BetaManagedAgentsSessionThreadStats { active_seconds, duration_seconds, startup_seconds } or null

Timing statistics for a session thread.

active_seconds: optional number

Cumulative time in seconds the thread spent actively running. Excludes idle time.

formatdouble
duration_seconds: optional number

Elapsed time since thread creation in seconds. For archived threads, frozen at the final update.

formatdouble
startup_seconds: optional number

Time in seconds for the thread to begin running. Zero for child threads, which start immediately.

formatdouble
status: BetaManagedAgentsSessionThreadStatus

SessionThreadStatus enum

One of the following:
"running"
"idle"
"rescheduling"
"terminated"
type: "session_thread"
updated_at: string

A timestamp in RFC 3339 format

formatdate-time
usage: BetaManagedAgentsSessionThreadUsage { active_seconds, cache_creation, cache_read_input_tokens, 4 more } or null

Cumulative token usage for a session thread across all turns.

next_page: optional string or null

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

List Session Threads

curl https://api.anthropic.com/v1/sessions/$SESSION_ID/threads \
    -H 'anthropic-version: 2023-06-01' \
    -H 'anthropic-beta: managed-agents-2026-04-01' \
    -H "X-Api-Key: $ANTHROPIC_API_KEY"
{
  "data": [
    {
      "id": "sthr_011CZkZVWa6oIjw0rgXZpnBt",
      "agent": {
        "id": "agent_011CZkYqphY8vELVzwCUpqiQ",
        "description": "A focused research subagent.",
        "mcp_servers": [
          {
            "name": "example-mcp",
            "type": "url",
            "url": "https://example-server.modelcontextprotocol.io/sse"
          }
        ],
        "model": {
          "id": "claude-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
      },
      "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": {
        "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
        }
      }
    }
  ],
  "next_page": "page_MjAyNS0wNS0xNFQwMDowMDowMFo="
}
Returns Examples
{
  "data": [
    {
      "id": "sthr_011CZkZVWa6oIjw0rgXZpnBt",
      "agent": {
        "id": "agent_011CZkYqphY8vELVzwCUpqiQ",
        "description": "A focused research subagent.",
        "mcp_servers": [
          {
            "name": "example-mcp",
            "type": "url",
            "url": "https://example-server.modelcontextprotocol.io/sse"
          }
        ],
        "model": {
          "id": "claude-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
      },
      "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": {
        "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
        }
      }
    }
  ],
  "next_page": "page_MjAyNS0wNS0xNFQwMDowMDowMFo="
}