A Diff Autopsy Sheet for Free-Model Changes: Flag Deletions, Churn, and Repo Shape Before Review

Why this is worth reading: a free coding model can return a patch that passes your test suite and still create a costly change. It might delete a seed file, flip an executable bit, rewrite a 400-line module to change two lines, or bundle a new dependency lockfile into a one-line fix. You do not need to read every line first. You need to read the shape of the diff. Most code review tools show you a unified diff and ask you to evaluate it line by line. That is the wrong order for model-generated work. The first pass should be a shape check: which paths changed, what was deleted, whether file modes or binary content changed, and how much churn each file carries. This article gives you a small local script that prints that shape and a decision table for acting on it. Start from the diff metadata, not the code git diff can print the raw numbers used to build the visual diff you see on GitHub or GitLab. The --numstat option outputs one line per file with added lines, removed lin