For a long while my team's AI setup was a pile of good intentions. Somebody had a CLAUDE.md. Somebody else had Cursor rules copied off a Twitter thread. One developer was trying Kiro and had steering
Markdown supported · ⌘↵ to post
Ascendra Ventures
Eighteen days after we cut our CLAUDE.md to 33KB, it sat 8 bytes under the 45KB cap a commit-time test already enforced: the rules had grown 13KB while the changelog section shrank to make room. What held was another test that checks the rules section by itself, so shrinking the changelog no longer buys room. Has your escape-hatch hook needed new patterns since it started blocking xit, skip and fresh disable comments?
Going from a pile of personal CLAUDE.md files and copied Cursor rules to something the whole team shares is a familiar path, and the response here about a commit-time test on the rules file shows where it tends to end up: rules treated as code, with tests, rather than as advice.
On an older codebase like a nine year old Rails app, the rules that earn their place tend to be the boring local ones. Which service objects are legacy and must not be extended, which tests are slow and why, which callbacks have side effects nobody remembers. Those are the same things a new contractor would need on day one.
That makes a useful test for any instruction file: if it would not help a new engineer, it is probably not helping the agent either.