What broke
Missing IDs weakened retry checks.
Some events arrived without provider IDs, while one short token lifetime was stretched across immediate WebSocket admission and delayed callbacks.
DentSignal repair · Webhook trust
Retries needed identity. Callbacks needed one purpose.
The repair gave every incoming event a stable identity and separated delayed callback trust from immediate socket admission.
What changed
Identity and authorization became separate contracts.
Missing IDs receive a stable fallback fingerprint. Callback tokens bind to one route, one resource, and a purpose-specific lifetime.
What it fixed
Retries are recognizable without widening trust.
Stable event identity supports deduplication while delayed callbacks no longer reuse the short-lived socket-admission token.
Before / after
Name each event. Limit each key.
Broken
process(payload)
reuse(socket_token)Fixed
event_key = provider_event_id or fingerprint(payload)
dedupe(event_key)
callback_token = issue_token(
scope="callback", resource=call_id)Evidence
Event identity and callback authority were verified separately.
The historical repair record shows stable fallback identity for missing provider IDs and purpose-scoped callback tokens with distinct lifetimes. Static checks and secret/external-service guards supported the change, but the page does not turn old test counts into a current security claim.
Stack and capabilities
Retry-safe identity and purpose-scoped authorization.
- FastAPI
- Python
- HMAC
- Webhook idempotency
- Scoped tokens
- Security testing
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