Sign in
Webhooks

A2A Task Event

Fired for A2A task-ledger events on an agent identity with an active A2A subscription. Target identities receive a2a.task.created, a2a.task.message, and a2a.task.canceled; caller identities receive a2a.sent_task.updated. Automatic delivery retries are bounded and may deliver an event more than once, so consumers should deduplicate with the stable event id.

If your organization has a signing key, every webhook includes three headers:

  • X-Inkbox-Request-ID — UUID for deduplication.
  • X-Inkbox-Timestamp — Unix timestamp in seconds.
  • X-Inkbox-Signature — sha256={HMAC-SHA256 hex digest} over {request_id}.{timestamp}.{raw_body}.
postWebhook/a2a

Payload

idstring required

Stable per-event id (evt_...); idempotency key across retries.

event_type'a2a.task.created' | 'a2a.task.message' | 'a2a.task.canceled' | 'a2a.sent_task.updated' required
timestampstring date-time required

Response

Successful Response

{"stackTrail":"webhooks:/a2a:post:responses:200:content:application/json:schema","oasType":"schema","type":"unknown"}

Changes

Webhooks have no change history: a webhook is keyed by its event name rather than a path and method, so no recorded change can name it.