AGENTS.md & CLAUDE.md linter
Paste an agent instruction file and get instant, local checks. Nothing is uploaded.
Results
Paste a file and press Lint file.
What the linter checks
| Check | What it looks for |
|---|---|
| Size | Characters, lines and an estimated token count; warnings near Claude Code's ~200-line guidance, Devin's 12,000-character rule cap and Codex's 32 KiB limit. |
| Commands | Missing build or test commands (npm/pnpm/yarn, pytest, go test, cargo, make, mvn, gradle…). |
| Vague rules | Phrases such as "best practices", "clean code", "be careful", "as needed". |
| Secrets | API keys (OpenAI, Anthropic, AWS, GitHub, Slack, Google), private keys, connection strings with passwords, password= lines. |
| Conflicts | Contradictions such as npm vs pnpm, tabs vs spaces, 2 vs 4 spaces, single vs double quotes, "always X" vs "never X". |
| Absolute paths | Machine-specific paths like /Users/alice or C:\ that break for teammates and CI. |
| Risky instructions | Telling the agent to skip permissions, use YOLO/bypass modes or never ask. |
| File type | CLAUDE.md without @AGENTS.md import, .mdc rules without frontmatter, GEMINI.md reminder about context.fileName. |
Need a starting point? Use the AGENTS.md generator. Want the file to work everywhere? Read one AGENTS.md for every agent.
FAQ
How long should AGENTS.md or CLAUDE.md be?
As short as possible. Anthropic suggests keeping each CLAUDE.md under about 200 lines; Codex stops reading instruction files at 32 KiB by default; Devin Desktop caps a workspace rule at 12,000 characters. Every line costs context on every request.
Why does the linter flag vague rules?
Rules like 'write clean code' or 'follow best practices' give the agent nothing to act on. Replace them with checkable instructions: which formatter, which test command, which directory.
Are instruction files enforced?
No. AGENTS.md and CLAUDE.md are context, not enforcement. Anything that must never happen (deleting data, force-pushing, reading secrets) belongs in permission rules, a sandbox or a pre-tool hook.
Does the linter upload my file?
No. All checks run locally in your browser. Only aggregate counts (number of issues, size) are sent to analytics.