{ "feature_id": "F-023", "agent": "security", "verdict": "APPROVED", "summary": "Security approved. No new dependencies. Webhook signature is verified with constant-time HMAC and 5-minute tolerance. Idempotency is enforced at the database level by the unique constraint on (provider, provider_event_id).", "evidence": [ "cd project && npm audit --audit-level=high --omit=dev: found 0 vulnerabilities", "Reviewed StripePaymentProvider: uses createHmac and timingSafeEqual with bounded timestamp tolerance", "Reviewed payments_transactions table: UNIQUE (provider, provider_event_id) and CHECK constraints", "Reviewed webhook route: unauthenticated and signature-validated; no client payment status fields accepted" ], "timestamp": "2026-08-15T18:37:54Z" }