Your CLAUDE.md only grows. Every incident adds a rule, every preference becomes a paragraph, and six months in you have a file that reads like a wiki — and an agent that follows maybe half of it.
The uncomfortable mechanics: CLAUDE.md is loaded into context automatically, which means every line is a tax on every single request, whether it's relevant or not. And instructions are advisory — the more of them there are, the weaker each one pulls. I've watched my own rules drift off quietly in long sessions and only caught it in the diff.
So the real question isn't "what should I write in CLAUDE.md?" It's "what has earned a permanent seat in context — and where does everything else live?"
Claude Code gives you four places to put guidance, and they have very different cost models:
Destination
