Most model-backed review jobs do not fail because the model is bad. They fail because someone edited prompts/review.md at 4pm on a Friday, and nothing in the pipeline noticed. AI-authored diffs keep arriving faster than human review capacity grows, so more teams are wiring a model call into the PR path. That is a reasonable move. The problem is that the prompt, the decoding settings, and the fixture set now behave like production code, while being versioned like a scratch note. This arti...