Cause

Idempotency-Key header is not a valid UUID v4.

Partner action

Send Idempotency-Key as a UUID v4.

Gando action (internal)

Check key format validation in with-partner-idempotency.ts.

Example response

{
  "error": {
    "code": "invalid_idempotency_key",
    "message": "Invalid Idempotency-Key format (expected UUID v4)",
    "requestId": "req_abc123"
  }
}