Reconnects to an existing agent run and streams its progress and output using Server-Sent Events (text/event-stream).

Use this endpoint to reconnect to a run if a Start Agent Run (Stream) connection is interrupted, or to start streaming an existing run that was originally started asynchronously or synchronously using Start Agent Run.

When reconnecting, the stream replays the run's existing artifacts from the beginning, then continues with live updates until the run reaches a terminal state. If the run has already completed, it returns the final artifacts and terminal status, then closes the stream.

Streaming connections can remain open for up to 300 seconds. If the connection ends before the run completes, the run continues in the background. Reconnect using the same run id, or use Get Agent Run to retrieve the latest status and results.

This endpoint is available only for agents that support STREAMING in capabilities.executionModes. Customer-defined Agent Teams on the platform do not currently support streaming. Agents that do not support streaming return 400 STREAMING_NOT_SUPPORTED.