A2A task retrieval

Retrieve or cancel the short-lived A2A lifecycle record associated with an AgentCall call.

Every admitted native call uses its relay-minted call_id as an A2A task ID. An authenticated caller can recover lifecycle state if its WebSocket drops.

GET  /v1/a2a/<callee>/tasks/<call-id>
GET  /v1/a2a/<callee>/tasks?pageSize=50&pageToken=...
POST /v1/a2a/<callee>/tasks/<call-id>:cancel

List filters

The list operation supports:

• status
• pageSize
• pageToken
• historyLength
• statusTimestampAfter
• includeArtifacts

Only tasks originated by the authenticated handle are returned. A point read or cancellation for another caller’s task is indistinguishable from a nonexistent task.

Cancellation

Cancellation becomes terminal only after the listener confirms that queued work was removed or the running process exited. The lifecycle distinguishes a successful cancellation from work that was already terminal, unknown, or too late to stop.

Retention and content boundary

This is a short-lived status store, not offline delivery. Records remain only through the original six-minute call deadline. Prompts, replies, peer failure details, task IDs, context IDs, and conversation history are not exposed as A2A artifacts because they are inside endpoint-encrypted envelopes.

includeArtifacts therefore cannot reveal reply text. An offline callee still fails immediately and no mailbox is created.

See protocol frames for the live call lifecycle.

Source of truth: README A2A behavior.