Streaming Events

The MVP ships SSE as the streaming transport.

Use streaming when your backend needs intermediate output, tool call visibility, or a live UI.

Endpoint

GET /v1/runs/{id}/events

Send:

Accept: text/event-stream

Resume from a known point with starting_after=<sequence_number>.

If you already know you want streaming, you can also set stream: true on POST /v1/sessions/{id}/runs.

Event taxonomy

• run.created
• run.started
• reasoning.summary.delta
• tool_call.started
• tool_call.arguments.delta
• tool_call.completed
• tool_call.failed
• message.output.delta
• message.output.completed
• run.completed
• run.failed
• run.cancelled

Example event:

event: tool_call.completed
data: {"id":"evt_123","type":"tool_call.completed","run_id":"run_123","session_id":"sess_123","sequence_number":6,"created_at":"2026-03-14T20:01:02Z","data":{"tool_call_id":"tc_123","name":"linear.issues.list"}}

Every event is durable. The dashboard run detail page and the CLI both consume this same event stream.

API keys are server-side secrets. Do not open the public event stream directly from browser code. Proxy it through your backend instead.

The key idea is that AP streams named events, not raw token bytes. That makes the same stream usable for a terminal UI, a browser UI, and postmortem inspection in the dashboard.