Start task thread
POST
/v1/tasks/{taskId}/start-threadCreate the first thread for a task, link it back to the task, and optionally move the task into in_progress.
How to call this endpoint
Every ACP API request uses bearer authentication. The examples here show the actual request path, auth header, and body shape that the platform expects.
Path, query, and header parameters
These parameters control which ACP object the endpoint acts on and how the request is processed.
Path parameters
| Name | Location | Type | Required | Description |
|---|---|---|---|---|
| taskId | path | string | Yes | Task ID |
Query parameters
None.
Body schema
Content type: application/json · Optional
| Field | Type | Required | Description |
|---|---|---|---|
| environmentId | string | No | Computer ID. |
| agentId | string | No | Agent ID. |
| moveToInProgress | boolean | No | — |
| metadata | object | No | Free-form metadata object. |
What the API returns
Each response code below includes the documented payload shape for the ACP API.
201Task thread createdapplication/json
| Field | Type | Required | Description |
|---|---|---|---|
| thread | object | No | — |
| thread.id | string | No | Unique identifier. |
| thread.projectId | string | No | Project ID. |
| thread.environmentId | string | No | Computer ID. |
| thread.agentId | string | No | Agent ID. |
| thread.title | string | No | Display title. |
| thread.task | string | No | — |
| thread.appId | string | No | — |
| thread.status | active | running | completed | failed | cancelled | No | Current lifecycle status. |
| thread.messageCount | integer | No | — |
| thread.lastMessageAt | string | No | — |
| thread.lastMessagePreview | string | No | — |
| thread.inputTokens | integer | No | — |
| thread.outputTokens | integer | No | — |
| thread.totalCost | number | No | — |
| thread.environmentMinutes | number | No | — |
| thread.metadata | object | No | Free-form metadata object. |
| thread.teamExecution | object | No | — |
| thread.teamExecution.mode | team | No | — |
| thread.teamExecution.teamAgentId | string | No | — |
| thread.teamExecution.teamAgentName | string | No | — |
| thread.teamExecution.orchestrator | object | No | — |
| thread.teamExecution.orchestrator.agentId | string | No | Agent ID. |
| thread.teamExecution.orchestrator.agentName | string | No | — |
| thread.teamExecution.orchestrator.claudeAgentName | string | No | — |
| thread.teamExecution.subagents | object[] | No | — |
| thread.teamExecution.subagents[].agentId | string | No | Agent ID. |
| thread.teamExecution.subagents[].agentName | string | No | — |
| thread.teamExecution.subagents[].claudeAgentName | string | No | — |
| thread.subagentActivity | object[] | No | — |
| thread.subagentActivity[].agentId | string | No | Agent ID. |
| thread.subagentActivity[].agentName | string | No | — |
| thread.subagentActivity[].claudeAgentName | string | No | — |
| thread.subagentActivity[].eventCount | integer | No | — |
| thread.subagentActivity[].lastActiveAt | string | No | — |
| thread.subagentActivity[].teamAgentId | string | No | — |
| thread.subagentActivity[].teamAgentName | string | No | — |
| thread.environmentName | string | No | — |
| thread.agentName | string | No | — |
| thread.createdAt | string | No | ISO 8601 timestamp. |
| thread.updatedAt | string | No | ISO 8601 timestamp. |
| task | object | No | — |
| task.id | string | No | Unique identifier. |
| task.userId | string | No | User ID. |
| task.projectId | string | No | Project ID. |
| task.releaseId | string | No | — |
| task.title | string | No | Display title. |
| task.description | string | No | Human-readable description. |
| task.status | backlog | todo | in_progress | blocked | done | No | Current lifecycle status. |
| task.priority | low | medium | high | urgent | No | — |
| task.sprintId | string | No | — |
| task.assigneeAgentId | string | No | — |
| task.dependencyIds | string[] | No | — |
| task.linkedThreadIds | string[] | No | — |
| task.lastStartedThreadId | string | No | — |
| task.scheduledStartAt | string | No | — |
| task.scheduledEndAt | string | No | — |
| task.dueAt | string | No | — |
| task.completedAt | string | No | ISO 8601 timestamp. |
| task.sortOrder | number | No | — |
| task.metadata | object | No | Free-form metadata object. |
| task.createdAt | string | No | ISO 8601 timestamp. |
| task.updatedAt | string | No | ISO 8601 timestamp. |
409Task is blocked by dependencies or already started
None.