version: "1.0.0" name: chestertons-fence description: Understand why existing code exists before removing, simplifying, or refactoring it — Chesterton's Fence. Use before deleting code that looks dead or unnecessary, before simplifying anything you didn't write, or when a "cleanup" urge shows up mid-task. Companion to surgical-change and simplicity-budget — this is the check that runs before either of those act.

Chesterton's Fence (router)

This skill is tuned per model. Pick the file that matches the model actually running, and apply it in full — the core discipline (understand before you touch) is the same everywhere, but how the investigation gets done and what to watch for differs by tier.

Read the file matching the model actually running before applying this skill.

Running a model not listed above (an older generation, a different model family entirely)? sonnet-5.md carries the fullest general-purpose version of the underlying procedure — read that one rather than skipping this skill.