Why Hand-Maintained AI Rules Files Go Stale and What to Do Instead

Developers commonly create rules files like .cursorrules or CLAUDE.md to guide AI coding agents, but these files quickly become outdated as teams make new decisions without updating them. A stale rules file can be more harmful than no file at all, since AI agents treat its contents as authoritative and propagate outdated patterns rapidly across a codebase. The core problem is structural: hand-maintained documentation relies on humans pausing mid-workflow to record decisions whose benefits are deferred, a habit that rarely sticks. The proposed alternative is to capture decisions where they already occur — in pull request threads, Slack channels, and tickets — and automatically generate agent-readable rules from that source material. This approach treats the rules file as a continuously updated projection of real team decisions rather than a manually curated document.