12.18A robust idempotency record

Conceptually:

{
  "idempotencyKey": "REQ-123",
  "status": "COMPLETED",
  "requestHash": "abc...",
  "result": {
    "salesforceId": "001ABC"
  },
  "createdAt": "...",
  "expiresAt": "..."
}

Why store request hash?

Because someone might reuse:

REQ-123

with a completely different payload.