Lean CLAUDE.md template (under 200 lines)

Anthropic recommends keeping each CLAUDE.md under 200 lines. Longer files use more context and get followed less. This one is under 50.

Preview: CLAUDE.md

## Commands

- Dev: `[npm run dev]`
- Build: `[npm run build]`
- Test one file: `[npm test -- path/to/file.test.ts]`
- Lint and types: `[npm run lint && npx tsc --noEmit]`

## Workflow

- Plan first for anything touching more than three files. Show the plan before editing.
- Prefer running single tests over the whole suite.
- After a series of changes, run the type check and lint, and paste the real output.
- Keep diffs small. Don't refactor code you weren't asked to touch.

## Project rules Claude can't guess

- [Example: API handlers live in `app/api/`; use the error helper in `lib/errors.ts`.]
- [Example: Dates are stored in UTC and shown in the user's time zone.]
- [Example: Never edit an applied migration in `supabase/migrations/`; add a new one.]

## Security

What's inside

• Commands, workflow, project rules, security, gotchas
• An @AGENTS.md import line, so it works alongside AGENTS.md
• Maintainer notes in HTML comments, which Claude Code strips before loading

How to use it

1. Save as CLAUDE.md in your repo root.
2. No AGENTS.md? Delete the @AGENTS.md line.
3. Replace every [bracket].
4. Move long, occasional procedures into skills.

Who it's for

Claude Code users whose CLAUDE.md has grown too long, or who are starting fresh.

Related

• Universal AGENTS.md starter + bridge files
• What is AGENTS.md?
• What are agent skills?