MCP transport rate limit exceeded

Too many MCP protocol requests came from this address.

Resolution

Reduce protocol polling and wait for the transport window to reset.

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.