Unsupported media type

The MCP endpoint received an unsupported request content type.

Resolution

Send MCP JSON-RPC requests with Content-Type: application/json.

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.