Webhook (Agent Trigger)

A webhook is an HTTP callback used to trigger an AI agent in response to events in external systems, such as a new ticket, a payment, or a calendar event.

Webhooks must be authenticated (typically with HMAC signatures) to prevent unauthorised actors from triggering agent actions by sending spoofed events.

Closely related concepts include Agent Hijacking, Trust Chain, Agent Card, Agent Passport. Each is defined in the Prefactor glossary.