Setting up CLAUDE.md files

Reading time: 5 minQuick Tutorial

Configure project-specific settings and context to maximize Claude Code's effectiveness for your specific projects.

What is CLAUDE.md?

CLAUDE.md is a special configuration file that allows you to provide persistent context and project-specific settings to Claude Code. It helps Claude understand your project better and provide more accurate assistance.

Key Benefits

Persistent project context across sessions
Custom configuration for project-specific needs
Improved code recommendations
Better understanding of project architecture
Reduced need for repetitive explanations

Creating a Basic CLAUDE.md File

Let's start with a basic CLAUDE.md file structure:

Step 1: Create the File

Create a file named CLAUDE.md in your project's root directory:

# Project: My Awesome App

## Project Description
A brief description of what your project does and its main features.

## Tech Stack
- Frontend: React, TypeScript
- Backend: Node.js, Express
- Database: MongoDB
- Testing: Jest, React Testing Library

## Code Conventions
- We use Prettier for formatting
- ESLint for linting
- Functional components with hooks for React
- 2-space indentation
- camelCase for variables and functions
- PascalCase for components and classes

## Project Structure
- /src - Main source code
  - /components - React components
  - /pages - Page components
  - /api - API routes
  - /utils - Utility functions
  - /hooks - Custom React hooks
  - /styles - CSS/SCSS files
- /public - Static assets
- /tests - Test files

Step 2: Add Context-Specific Sections

Enhance your CLAUDE.md with more specific context:

## Important Notes
- User authentication uses JWT stored in HttpOnly cookies
- API calls should use the client utility in /src/utils/api.ts
- New components should have a companion test file
- State management uses React Context + useReducer

## Known Issues
- Performance issues with large data sets in the dashboard component
- Mobile menu animation is choppy on older iOS devices

## Future Plans
- Implementing real-time updates with WebSockets
- Adding a dark mode theme
- Migrating to Next.js for improved SEO

Advanced Configuration

Take your CLAUDE.md file to the next level with these advanced features:

Custom Instructions

Add specific instructions for how Claude should behave when working with your project:

## Instructions for Claude
- Always suggest TypeScript types for new functions
- Prioritize performance optimizations
- Use React Query for data fetching
- Follow the existing error handling pattern
- Include JSDoc comments for public functions
- Prefer functional programming approaches

Environment Configuration

Provide information about the development environment:

## Environment Setup
- Node.js v16+
- npm scripts:
  - `npm start` - Start development server
  - `npm test` - Run tests
  - `npm run build` - Build for production
  - `npm run lint` - Run linter
- Environment variables (examples, not actual values):
  - API_URL=http://localhost:3001
  - DEBUG=false
  - FEATURE_FLAGS_ENABLED=true

Architecture Diagrams

Include Mermaid diagrams to visualize architecture:

## Architecture

```mermaid
graph TD
    A[Client] --> B[API Gateway]
    B --> C[Auth Service]
    B --> D[User Service]
    B --> E[Content Service]
    C --> F[(Auth DB)]
    D --> G[(User DB)]
    E --> H[(Content DB)]
```

## Component Relationships

```mermaid
graph TD
    A[App] --> B[Layout]
    B --> C[Header]
    B --> D[Main Content]
    B --> E[Footer]
    D --> F[Dashboard]
    F --> G[UserStats]
    F --> H[ActivityFeed]
    F --> I[Recommendations]
```

Best Practices

Follow these best practices for maintaining effective CLAUDE.md files:

Keep It Updated

Update CLAUDE.md whenever project architecture changes
Add new sections as project complexity grows
Remove outdated information
Treat it as living documentation

Use Multiple CLAUDE.md Files

For larger projects, consider using multiple CLAUDE.md files in different directories:

/CLAUDE.md - Root project context
/frontend/CLAUDE.md - Frontend-specific details
/backend/CLAUDE.md - Backend-specific details
/docs/CLAUDE.md - Documentation guidelines

Version Control

Commit CLAUDE.md to your repository
Review changes to CLAUDE.md during code reviews
Consider adding CLAUDE.md updates to your Definition of Done