Webhooks

Agents propose webhook endpoint changes; an apply-scoped human or automation applies the durable proposal. Endpoint URLs must be HTTPS and pass server-side SSRF validation. Signing secrets are server-minted, reveal-once values and are never present in MCP inputs or results.

Consumers verify HMAC-SHA256 over <timestamp>.<exact raw body> before parsing. Use the event ID for deduplication. Delivery is at least once, retries use exponential backoff, ordering is best effort per user, and deliveries dead-letter after eight attempts.