What is CLAUDE.md?
CLAUDE.md is a plain text markdown file that acts as a local memory and configuration engine for Anthropic's Claude Code CLI utility. It stores project guidelines, coding rules, and build/test commands in your repository root, ensuring the assistant fits your exact stack specifications instantly upon startup.
Why do I need a CLAUDE.md file?
When you launch Claude Code in your project directory, the assistant operates inside your workspace but has zero context about how the code should compile, how tests are structured, or what patterns your team follows.
Without a CLAUDE.md, Claude has to guess or search your file tree. This wastes valuable API tokens, adds execution latency, and can result in incorrect code adjustments. A CLAUDE.md solves this by providing:
- Instant Command Maps: Direct references for compilation, test cases, and quality checks.
- Styling Standards: Immediate alignment with language patterns and layout guidelines.
- Code Consistency: Preventing the assistant from introducing styling clashes or anti-patterns.
A Minimal CLAUDE.md Template
A basic configuration file requires very little code. Here is a simple, highly explicit template that you can copy and customize:
# Build and Test Commands
- Build: `npm run build`
- Dev server: `npm run dev`
- Test: `npm test`
- Lint: `npm run lint`
# Code Style Guidelines
- Use React with TypeScript (SPA)
- Put custom hooks inside `src/hooks`
- Formatting: 2 spaces indent, no semi-colonsNext Steps
If you are setting up your project, read our detailed setup guide or explore comparative tools: