Optionalcontext_Optionaltask_OptionalstatusOptionalpayloadFull AdCP response payload. Populated on webhook_received and
protocol/status events. INTENTIONALLY omitted on webhook_duplicate
to avoid re-logging potentially-sensitive data on every retry — the
originating webhook_received event already carries it. Correlate
the two via idempotency_key.
Optionalidempotency_Webhook idempotency key when available. Present on webhook_received
and webhook_duplicate events from MCP envelopes, enabling
correlation between a first delivery and its retry echoes.
Activity event for logging/observability