Agent Channel - Aether

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). Every turn-owned event carries a required, non-zero UUID conversationTurnId; conversation.truncated and slash_commands.updated are task-level events and carry none. Message-scoped events also carry messageId; most events carry a provider turnId.

Canonical tool updates

Tool cards are read from the API conversation-turn activity endpoint, not synthesized from WebSocket events. Subscribe to task_read_model_revisions and refetch the turn summaries and revision-keyed activity when it changes, including after reconnect. A result observed by a later execution updates the card in its original conversation turn.

Message and stream events

assistant_message and thinking arrive as token deltas followed by a completion. These carry the durable conversationTurnId, plus messageId and turnId.

`kind`	Payload	Meaning
`assistant_message.delta`	`{ "delta": "..." }`	Incremental assistant text
`thinking.delta`	`{ "delta": "..." }`	Incremental reasoning text
`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",
  "conversationTurnId": "650e8400-e29b-41d4-a716-446655440000",
  "messageId": "msg-9",
  "turnId": "turn-1",
  "payload": { "delta": "I'll create the route" }
}

Turn settlement

Turn completion, failure, and pending input are authoritative task/conversation read-model state, not agent WebSocket announcements. Refresh canonical conversation snapshots on task revision changes. Keep accepted content visible until the same snapshot includes its durable replacement; an older revision cannot clear a newer execution’s content. Respond to pending input 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 pending question	`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 turn summaries and per-turn activity over REST — history is not replayed on the socket.

​Client to Server

​subscribe

​unsubscribe

​Server to Client: task_event

​Canonical tool updates

​Message and stream events

​Turn settlement

​Other events

​Driving a Task

Client to Server

`subscribe`

`unsubscribe`

Server to Client: `task_event`

Canonical tool updates

Message and stream events

Turn settlement

Other events

Driving a Task