repo-sightlisted

# repo-sight — see the repo before you read it The first hour you spend on a new codebase decides whether you understand it in a day or in a month. This skill encodes a single move: **interrogate the repository's history, structure, and behavior with cheap probes before opening any file**, then return a ranked reading list with explicit caveats about what the probes could not see. This is a synthesis of [Ally Piechowski's *"The Git Commands I Run Before Reading Any Code"*](https://piechowski.io/post/git-commands-before-reading-code/), Adam Tornhill's *Your Code as a Crime Scene* (behavioral code analysis), and the classical engineering practice of tracer-bullet / vertical-slice exploration. --- ## §1 — Mental model: three lenses, golden intersections Any attempt to understand unfamiliar code looks through one of three independent lenses. **Each lens is blind in its own way; truth lives in their intersections.** Refuse to draw conclusions from a single lens. | Lens | Question | How to look | Blind spot in isolation | |---|---|---|---| | **STRUCTURE** (static) | what exists and what depends on what | dir tree, language/size (`tokei`, `scc`), import graphs, manifests, types/schemas/API surface, public exports | looks clean, hides that one tidy module is patched every week | | **HISTORY** (time) | how it became this and where it hurts | churn, co-change, bug clusters, velocity, bus factor, firefighting; `git log -p`, `git blame`, `git bisect` | finds the hot file but not *w