Your CLAUDE.md is too long. The 200-line ceiling that actually works.

Most CLAUDE.md files we see are too long. Five thousand lines, six thousand. Every team rule, every legacy comment, every "I once tried this and it didn't work" footnote. The author feels productive writing them. The model reads the first 800 lines and ignores the rest.

There's a known ceiling, and it's lower than people think.

The 200-line rule

The community consensus that's hardened over the last six months: keep CLAUDE.md under 200 lines. Anthropic's own Claude Code best practices and HumanLayer's CLAUDE.md guide both land in the same place. Past that, the model treats the file the way you treat a 200-page Terms of Service — present, technically read, not actually attended to.

The cited number for how many instructions Claude reliably follows is around 150. Not lines — instructions. Each "do this," "never that," "use X not Y" is one instruction. A CLAUDE.md with 200 distinct rules already lives at the edge of what's tracked; 500 is comfortably past it.