IME people are usually shoving their personal preferences in CLAUDE.md, sometimes automatically as the agent updates the file with that developer's pet peeves.
- Right now at $WORK, CLAUDE.md has a line saying to put one-off scripts in some gitignored place. That's fine if they're not worth checking in (IMO, you should build the tooling which would have made the script easy and check that in, but whatever), but that AI rule doesn't really keep them from being checked in -- developers manually review every line of code and decide what to check in -- that's just somebody deciding they'd rather not have to think so hard when running git add. Which is fine, but it directly conflicts with my preference for all AI-generated files to be plainly visible as a diff or with git status or something. They have a different diffing strategy, which is also fine, but that's just a dev's personal preference encoded in a whole-team doc.
- Or, I have a prompt I use to encourage higher quality code before I have to manually inspect it. It basically says "delete $200 and 1hr." For somewhat obvious reasons, I don't run it on every piece of code the AI shits out. I make it available in the project for people who want to use it, but I don't even want it in my CLAUDE.md, much less the team's.
- Similarly with whether to use git for checkpointing. I prefer to check the AIs output at each step. A colleague prefers to have it save its progress using git in 30+ commits on a side branch and then check them all at once. One of those workflows was in CLAUDE.md and absolutely is not anymore -- it's quite appropriate for a single developer's AI settings, but not for the team as a whole.
Those settings files are a lot closer to .vscode directories or other dev-specific editor configuration. Project-specific information should be exposed differently.