CLAUDE.md Files

CLAUDE.md is a special file that provides persistent context to Claude Code. Place it in your project root to give Claude information about your codebase.

What to include

# Project Name

Brief description of what this project does.

## Tech stack

- Language: TypeScript
- Framework: Next.js 15 (App Router)
- Database: PostgreSQL with Prisma ORM
- Testing: Vitest + Playwright

## Build and test commands

- `npm run dev` — Start development server
- `npm run build` — Production build
- `npm run test` — Run unit tests
- `npm run test:e2e` — Run end-to-end tests
- `npm run lint` — Lint and format check

## Code conventions

- Use named exports, not default exports
- Prefer `interface` over `type` for object shapes
- Error handling: use Result types, not try/catch
- Tests go in `__tests__/` directories next to source files

## Project structure

- `src/app/` — Next.js routes
- `src/lib/` — Shared utilities
- `src/components/` — React components
- `prisma/` — Database schema and migrations

File locations

Claude Code looks for CLAUDE.md in several places:

Location	Scope
Project root `CLAUDE.md`	Loaded for everyone working on the project
`~/.claude/CLAUDE.md`	Your personal preferences across all projects
Subdirectory `CLAUDE.md`	Loaded when working in that directory

Tips

Keep it concise — Claude reads the whole file on every session
Focus on things that aren't obvious from the code itself
Include the exact commands to build, test, and lint
Document non-obvious conventions and decisions