HTTP 413
payload_too_largeMCP request body too large
The MCP request body exceeds the accepted transport limit.
Resolution
Reduce the request size and retry.
Response handling
Keep the response's request_id for diagnostics. Retry only transient rate limits and 503 responses, respecting Retry-After with bounded exponential backoff and jitter. For monthly_quota_exceeded, stop polling until RateLimit-Reset or upgrade. Correct 400, 401, 403, and 406 requests before retrying.