Use Claude.md to Make Coding with Claude Smarter!

Tired of explaining the same patterns and rules to Claude every time you start a new project? With Claude Code and the Claude.md file, you can eliminate that hassle entirely. In this guide, we’ll explore how to maximize the efficiency of AI pair programming using Claude.md, complete with practical examples.

Claude Code isn’t just another AI coding tool—it’s a powerful pair programming partner that understands your project context, learns your team’s development rules, and helps maintain consistent coding styles. At the heart of all this is the Claude.md file.

What is Claude.md?

Claude.md is a Markdown file that Claude Code automatically reads. Think of it as an onboarding document for new developers, except it’s for Claude. It’s your project’s guidebook, detailing the tech stack, development rules, workflows, and even unwritten conventions.

Every time you open a project, Claude Code reads this file and uses the information to generate optimized code for your project. Once it’s written, Claude remembers the details permanently, applying the same context across new sessions or branches.

How to Use Claude.md: Building Project Context

The biggest advantage of Claude.md is its ability to document “unwritten rules” for your project. For example, if your team uses ES modules but hasn’t explicitly documented it, Claude might generate code using the CommonJS format. By specifying your rules in Claude.md like this:

# Development Rules
- Use ES modules (import/export syntax)
- Wrap all API calls in try-catch blocks
- Avoid using the 'any' type in TypeScript

Claude will consistently follow these rules when generating code.

You can also define your directory structure and clarify the roles of each folder:

# Project Structure
- `src/components`: Reusable UI components
- `src/lib`: Core business logic
- `src/utils`: Helper functions
- `scripts/`: Build and deployment scripts

Best Practices for Claude.md

Specify Your Tech Stack and Versions

Version details are crucial. For example, Next.js 13 and 15 require completely different approaches:

# Tech Stack
- Framework: Next.js 14
- Language: TypeScript 5.2
- Styling: Tailwind CSS 3.4
- Database: Prisma 5.x + PostgreSQL
- State Management: Zustand 4.x

Detail Development Rules

Include specific rules for Claude to follow:

# Development Rules
- Wrap all API calls in try-catch blocks
- Write components as functional (use React hooks)
- Use Tailwind classes instead of CSS-in-JS
- Follow Zustand store patterns for state management
- Use toast notifications for error handling

Document Your Workflow

Workflows are also key information:

# Workflow
- Branch naming: feature/TICKET-123-description
- Commit messages: Follow conventional commits
- Run linting and type checks before PRs
- Maintain at least 80% test coverage

Add Custom Instructions for Claude

Include any special notes or guidelines for Claude:

# Claude Instructions
- Be cautious when refactoring legacy code (don’t touch functioning code)
- Never skip accessibility checks
- Request confirmation for changes to config files
- Use TODO comments to highlight significant changes

Claude.md as a Context Switcher

Claude.md is more than just a set of rules—it acts as a “context switcher,” allowing you to apply different rules across various parts of your project.

Claude Code can find and combine CLAUDE.md files from multiple locations:

1. Home directory (~/.claude/CLAUDE.md): Applies globally to all Claude Code sessions.
2. Project root (your-repo/CLAUDE.md): The most common location, included in version control.
3. Subdirectory (your-repo/feature/CLAUDE.md): Applies to specific feature work.
4. Local overrides (CLAUDE.local.md): For personal settings (add to .gitignore).

For instance, you can create rules that apply only when working in an entity directory:

# src/entities/CLAUDE.md
- All entities must include Zod schema validation
- Only database-related logic allowed
- Business logic must be separated into the services layer

This ensures Claude automatically applies these rules when you work in the entity directory.

Evolving with Your Project

Claude.md should grow with your project. Update it as new features are added or development practices change. You can even ask Claude to review past commits and suggest updates for Claude.md:

claude -p "Review the last 10 commits and suggest new patterns or rules to include in CLAUDE.md"

Getting Started with Claude Code

Setting up Claude Code is simple.

Installation

# Install Claude Code CLI
npm install -g @anthropic-ai/claude-code

# Check version
claude --version

# Navigate to your project directory
cd your-project

# Start Claude Code
claude

Example Claude.md for a Next.js Project

Here’s a complete example Claude.md for a Next.js project:

# Project: E-commerce Dashboard

## Tech Stack
- Framework: Next.js 14.0 (App Router)
- Language: TypeScript 5.2
- Styling: Tailwind CSS 3.4
- Database: Prisma 5.x + PostgreSQL
- Authentication: NextAuth.js 4.x
- State Management: Zustand 4.x
- UI Components: Radix UI + Shadcn/ui

## Project Structure
- `app/`: Next.js 13+ App Router structure
- `components/ui/`: Reusable components based on Shadcn/ui
- `components/`: Business logic components
- `lib/`: Utilities and configurations
- `stores/`: Zustand state management
- `types/`: TypeScript type definitions

## Development Rules
- Write all components in TypeScript
- Prefer server components; use client components only when necessary
- API routes should be under the `/app/api/` directory
- Access the database only through Prisma Client
- Follow Zustand store patterns for state management
- Use only Tailwind CSS classes for styling

## Commands
- `npm run dev`: Start the development server
- `npm run build`: Run a production build
- `npm run lint`: Run ESLint
- `npm run type-check`: Run TypeScript checks
- `npx prisma studio`: Open the database GUI

## Coding Conventions
- Component names: PascalCase
- File names: kebab-case
- Variable names: camelCase
- Constants: UPPER_SNAKE_CASE
- No `I` prefix for interfaces

## Branching and Commit Messages
- Branch names: `feature/TASK-123-short-description`
- Commit messages: Follow Conventional Commits
- Run `npm run lint && npm run type-check` before opening a PR

## Claude Instructions
- Never use the `any` type
- Consider accessibility when creating components
- Use toast notifications for error handling
- Use Suspense boundaries for loading states
- Add TODO comments for significant business logic changes

How Claude and Claude.md Revolutionize Development

When used effectively, Claude.md can transform your development experience. You won’t need to repeat explanations, and Claude will generate code with a full understanding of your project’s context. Your team can maintain consistent coding styles, and new members can onboard quickly.

For complex enterprise projects, Claude.md ensures that Claude fully understands the intricacies of your project. With a well-written Claude.md, you can turn Claude into the ultimate pair programming partner!