Type the webhook payload as a WebhookPayload TypedDict so unknown or mistyped keys are caught statically #928

Deferred work · Phase 14.5: WebhookPayload TypedDict · severity Low · cost ~1-2 h · recorded in docs/roadmap/phase-14-5-pipeline-hardening.md:132

Summary

Phase 14.5 Task 4 replaced the free-form merge in _send(**extra) with a runtime allowlist plus scalar-type and base-field-collision screens; its optional follow-up — a typed WebhookPayload so a type checker flags unknown keys at edit time — was never built and is listed nowhere else. Low priority: the runtime allowlist already drops unregistered keys.

Condition or budget

None recorded ("Optional follow-up").

State today (re-checked 2026-10-09)

_send still builds payload: Dict[str, Any]; no TypedDict exists for it.

Related

It is only enforced if forgelm/webhook.py comes under a mypy gate (see the [tool.mypy] issue).

Acceptance criteria

• WebhookPayload (base keys plus NotRequired event-specific keys) types the payload, and a type check covers forgelm/webhook.py.

_{Recorded in docs/roadmap/phase-14-5-pipeline-hardening.md (read at f94595f) and re-checked against the code on 2026-10-09.}