## Identifiers

response.id The runtime response identifier. Use it for continuation as `previous_response_id`.

response.metadata.session_id The persistent session identifier. Use it for polling, turns, files, cancel, and archive.

## Terminal states

Streaming uses events such as `response.completed`, `response.incomplete`, and `response.failed`. Session polling reports a successful turn as `status: "done"`, not `completed`.

**Open standard**

Saving response.id for continuation and response.metadata.session_id for recovery follows the UHP session model, which chains follow-up turns on the previous response id rather than on the session itself.