Agent Channel

The agent channel is a one-way live feed of a task’s events. The client only subscribes and unsubscribes; the server streams task_event messages as the agent works. See the WebSocket overview for connecting.

You do not prompt the agent, answer its questions, or stop it over the WebSocket. Those are REST calls — see Driving a task. The agent channel is read-only event streaming.

Client to Server

Attach this connection to a task’s live event stream. You then receive every task_event for that task until you unsubscribe or disconnect.

{ "channel": "agent", "type": "subscribe", "taskId": "task-abc-123" }

`unsubscribe`

Detach from a task’s stream.

{ "channel": "agent", "type": "unsubscribe", "taskId": "task-abc-123" }

These are the only two client messages on this channel.

Server to Client: `task_event`

Every server message on the agent channel has type: "task_event". A kind field discriminates what happened. All events carry taskId and an optional createdAt (ISO 8601). Message-scoped events also carry messageId; most events carry a turnId.

Tool events

kind is tool_call.started, tool_call.completed, or tool_call.failed. These carry a toolCallId and a payload describing the tool call.

{
  "channel": "agent",
  "type": "task_event",
  "kind": "tool_call.completed",
  "taskId": "task-abc-123",
  "toolCallId": "tc-456",
  "turnId": "turn-1",
  "createdAt": "2026-02-20T10:30:00Z",
  "payload": {
    "name": "write_file",
    "input": { "path": "/src/routes/users.ts" },
    "display": { "label": "Write users.ts", "primary": "/src/routes/users.ts" },
    "status": "output-available",
    "itemType": "file_change",
    "result": "File written"
  }
}

The payload:

Field	Type	Description
`name`	string	Tool name
`input`	object	Tool arguments
`display`	object	UI labels: `label`, optional `primary`, optional `secondary`
`status`	enum	Tool status (below)
`itemType`	enum	Optional timeline classification (below)
`result`	string	Optional result text
`error`	string	Optional error text

status is one of input-streaming, input-available, output-available, output-error, output-denied, approval-requested, approval-responded. itemType classifies the timeline entry for rendering. Possible values: user_message, assistant_message, reasoning, plan, command_execution, file_change, file_read, mcp_tool_call, dynamic_tool_call, collab_agent_tool_call, web_search, web_fetch, image_view, task_tracking, subagent_invocation, review_entered, review_exited, context_compaction, error, unknown.

Message and stream events

assistant_message and thinking arrive as token deltas followed by a completion. These carry messageId and turnId.

`kind`	Payload	Meaning
`assistant_message.delta`	`{ "delta": "..." }`	Incremental assistant text
`thinking.delta`	`{ "delta": "..." }`	Incremental reasoning text
`assistant_message.completed`	`{ "content": "..." }`	Full assistant message
`thinking.completed`	`{ "content": "..." }`	Full reasoning block
`stream.complete`	(none)	The model stream for this message finished

assistant_message.delta

{
  "channel": "agent",
  "type": "task_event",
  "kind": "assistant_message.delta",
  "taskId": "task-abc-123",
  "messageId": "msg-9",
  "turnId": "turn-1",
  "payload": { "delta": "I'll create the route" }
}

Turn lifecycle events

A turn is one agent step. These carry a turnId.

`kind`	Payload	Meaning
`turn.completed`	`{ "status": "completed" }`	The turn finished
`turn.awaiting_input`	see below	The agent needs your input to continue
`turn.failed`	`{ "errorMessage": "..." }`	The turn failed

turn.awaiting_input additionally carries pendingInputId and toolCallId, and its payload names the tool requesting input:

{
  "channel": "agent",
  "type": "task_event",
  "kind": "turn.awaiting_input",
  "taskId": "task-abc-123",
  "turnId": "turn-1",
  "pendingInputId": "pending-7",
  "toolCallId": "tc-456",
  "payload": {
    "toolName": "ask_user",
    "input": { "question": "Use PostgreSQL or SQLite?" }
  }
}

Respond to this over REST (see below).

Other events

`kind`	Payload	Meaning
`conversation.truncated`	`{ "anchorMessageId": "..." }`	History was rolled back to a checkpoint (carries `messageId`)
`slash_commands.updated`	`{ "slashCommands": [...] }`	The set of available slash commands changed

Each slash command has name, description, and an optional input hint.

Driving a Task

The agent channel is receive-only. To act on a task, use the REST API:

Action	Endpoint
Start a task	`POST /v1/tasks`
Answer a question (`turn.awaiting_input`)	`POST /v1/tasks/{id}/respond`
Stop a task	`POST /v1/tasks/{id}/stop`

There is no public SSE or task-stream endpoint. Live task events reach clients only over this WebSocket. For prior conversation history, fetch conversation messages over REST — history is not replayed on the socket.

API Reference

Projects

Workspaces

Tasks

Environment Variables

Secret Files

Skills

Automations

Agent Profiles

Usage

Profile

Organizations

User Discovery

Pr Reviews

Pull Requests

Push Tokens

Cursor Auth

Claude Code Auth

Slack

Provider API Keys

Codex Auth

Sentry

Feedback

Notifications

OpenCode Auth

GitHub

Platform API Keys

User Settings

Billing

Linear

WebSocket

Client to Server

`unsubscribe`

Server to Client: `task_event`

Tool events

Message and stream events

Turn lifecycle events

Other events

Driving a Task

​Client to Server

​subscribe

​unsubscribe

​Server to Client: task_event

​Tool events

​Message and stream events

​Turn lifecycle events

​Other events

​Driving a Task

Client to Server

`subscribe`

`unsubscribe`

Server to Client: `task_event`

Tool events

Message and stream events

Turn lifecycle events

Other events

Driving a Task