API reference

Parse response streams by `data.type`.

HarnessRouter streams Server-Sent Events in an OpenAI Responses-style wire format with `data:` frames only.

Wire format

There are no event: lines. Every frame arrives as a default SSE message, and the event name is the type field inside the JSON payload.

First frame

data: {"type":"response.created","sequence_number":0,"response":{"id":"resp_...","status":"in_progress","metadata":{"session_id":"hsess..."}}}

response.created: Save response.id and response.metadata.session_id immediately.
response.output_text.delta: Append visible answer text.
response.output_item.added: Show sanitized tool or activity progress.
response.completed: Finalize successful UI state.
response.incomplete: Show partial result and offer Continue when appropriate.
response.failed: Show the classified failure or cancellation state.