Your CLAUDE.md is too long — and that's why Claude Code ignores it

Everyone hits the same wall with Claude Code. You add a rule to CLAUDE.md . It works. You add ten more. They mostly work. You add forty more — and now Claude is cheerfully ignoring the rule you care about most, the one that's been sitting there since day one. So you make it LOUDER , in caps, with three exclamation points. It still gets skipped. The instinct is to write more. The fix is almost always to write less . Here's why, and what to do instead. Instruction-following has a budget, and you're overdrawn This is the part most CLAUDE.md guides skip. Frontier models reliably follow on the order of 150–200 instructions at once — and adherence to any single rule drops as you stack more on top of it. It isn't a cliff; it's a slow tax. Every line you add makes every other line a little less likely to be honored. Now subtract what you don't control: Claude Code's own system prompt already spends a chunk of that budget before your file is even read. So the working budget for your project rules is smaller than the headline number — and a sprawling 300-line CLAUDE.md isn't 300 rules followed, it's maybe the first 150 followed well and the rest treated as ambience. The mental model that fixes everything downstream: CLAUDE.md is a budget, not a wishlist. You are not writing documentation. You are spending a scarce attention allowance, and every line competes with every other line. The test for every line: would you bet $5 it's followed? Go through your file line by line and ask one question of each rule: would I bet money this fires every time it's relevant? Three outcomes: Yes, and it's load-bearing — keep it. This is what the budget is for. Nice to have, but I wouldn't bet on it — cut it, or move it to a referenced file (below). It's diluting the rules you would bet on. It absolutely must happen every time — then it doesn't belong in CLAUDE.md at all. Make it a hook. That third category is the one people get wrong, so let's be concrete about it. Advisory vs. deterministic: