Free tool · Limits checked on 2026-10-04
Check your AGENTS.md and CLAUDE.md
Codex and Claude Code load these files into every session. Paste yours to see what's too long, what one agent never reads, and what shouldn't be there. It runs in your browser: nothing you paste is sent anywhere.
What it checks
| Check | Why it matters |
|---|---|
| AGENTS.md over 32 KiB | Codex stops adding instructions once all its AGENTS.md files together reach 32 KiB, its default project_doc_max_bytes. |
| Over 200 lines | Anthropic suggests keeping each CLAUDE.md under 200 lines. All of it loads into every session. |
CLAUDE.md without @AGENTS.md | Claude Code reads CLAUDE.md, and falls back to AGENTS.md only when there's no CLAUDE.md. |
@ imports in AGENTS.md | Imports are a Claude Code feature. Codex reads AGENTS.md as plain text. |
| API keys and private keys | These files are usually committed, and sent to your AI provider every session. |
| Paths into your home folder | C:\Users\you\… or /Users/you/… only works on your machine. |
| Lines that describe a moment | Dates, "currently" and TODOs go stale, and keep loading anyway. |
| Rules in both files | When CLAUDE.md imports AGENTS.md, Claude Code reads them twice. |
The token count is a rough guide, at about four characters a token. Sources: Claude Code's memory docs and Codex's AGENTS.md docs.
Where the rest goes
An instructions file is for rules that rarely change. What agents find out as they work goes stale in it, so it suits a hand-off file or notes better. The guides compare the options, starting with the free ones: