Discard legacy network allowlists, report the actual loopback-only runtime contract, and return a generic safe error if the final diagnostic reply boundary fails.
Redact every diagnostic response at the agent boundary, fail closed when sanitization cannot complete, and remove Windows, UNC, and slash-UNC paths from returned data. Preserve benign text while removing complete configured secret values, including nested JSON escapes and quoted HTML credential fields. Add focused regression coverage for collector errors, successful responses, support bundles, path variants, and punctuation secrets.