A nightly pipeline sends batches of scanned PDFs to the Claude API. Its error handler retries every non-200 response five times with backoff. Logs show three recurring patterns that never succeed on retry: 413 request_too_large on requests that bundle many large PDFs, 400 invalid_request_error on malformed content blocks, and 401 authentication_error after a key was revoked. Which change to the handler is correct?