Why This Little File Makes a Big Difference

Here's the thing about AI coding assistants: they're incredibly smart, but they're not mind readers. Drop an AI into a codebase without context and it'll make assumptions. Sometimes those assumptions are wrong.

CLAUDE.md is a simple Markdown file that lives in your project root. AI assistants read it automatically. Think of it like onboarding a new team member—except this team member can read really, really fast.

Real talk: A good CLAUDE.md can cut your "no, not like that" corrections by 50-70%. That's not hype—it's just what happens when you give context upfront instead of fixing things afterward.

A CLAUDE.md file open in VS Code editor — A CLAUDE.md file open in VS Code

The Four Sections Every CLAUDE.md Needs

You don't need to write a novel. These four sections cover 90% of what your AI needs to know:

1. Project Overview

What does this thing do? Two sentences max. This sets the mental model for everything else.

## Project Overview

TaskFlow is a project management app for remote teams.
Built with Next.js 15 and PostgreSQL. Focus on real-time
collaboration and Slack integration.

2. Commands

What commands does your project use? List them all. The AI will actually use these instead of guessing.

## Commands

```bash
npm run dev          # Start dev server (localhost:3000)
npm run build        # Production build
npm run test         # Run all tests
npm run test:watch   # Tests in watch mode
npm run db:migrate   # Run Prisma migrations
```

3. Architecture

Where does stuff go? This is huge for the AI knowing where to put new files.

## Architecture

### Directory Structure
- `src/app/` - Next.js App Router pages
- `src/components/` - React components
- `src/lib/` - Utilities (no React)
- `src/hooks/` - Custom React hooks
- `src/db/` - Prisma schema and queries

### Key Patterns
- Server Components by default
- Client Components only when needed
- Zustand for client state

4. Coding Standards

The "do this, don't do that" section. Be specific—vague rules get vague results.

## Coding Standards

### Do
- Use TypeScript strict mode
- Write tests for new features
- Keep functions under 50 lines
- Use descriptive variable names

### Don't
- Use `any` type (use `unknown` instead)
- Skip error handling
- Use inline styles (use Tailwind)
- Commit console.logs

Level Up: Advanced Tricks

Show, Don't Just Tell

One good code example beats ten rules. Show what "good" looks like in your project:

### Component Pattern

```tsx
// How we do server/client splits here:
export default async function UserList() {
  const users = await db.user.findMany()
  return <UserListClient users={users} />
}

// UserListClient.tsx - 'use client' at top
```

Point to Key Files

Help the AI find the important stuff quickly:

### Key Files

| File | Purpose |
|------|---------|
| `src/db/schema.prisma` | Database schema |
| `src/lib/auth.ts` | Authentication logic |
| `src/types/index.ts` | Shared type definitions |

Explain Your Domain

The AI doesn't know your business logic. Spell it out:

### Business Logic

- **Workspace**: A team's shared space
- **Project**: A collection of tasks
- **Task**: A unit of work
- Tasks can only be assigned to Workspace members
- Free tier: max 5 members per Workspace

Claude Code terminal reading context from CLAUDE.md — Claude Code reading context from CLAUDE.md

Mistakes That'll Trip You Up

Being Too Vague

"Write clean code" means nothing. "Functions under 50 lines, no nested callbacks deeper than 3 levels" means something.

Writing Too Much

If your CLAUDE.md is 1000 lines, the important stuff gets buried. Aim for under 500 lines. Use bullet points and tables.

Letting It Go Stale

Outdated docs cause more problems than no docs. When you change a pattern, update CLAUDE.md. Seriously.

Skipping Business Context

The AI has no idea what a "workspace" or "subscription tier" means in your app. Explain the concepts.

Start Here (Quick Wins)

Don't have time for everything? These four things give you the biggest bang for your buck:

1
Add your test command
The AI will run tests after changes if it knows how. Game changer.
2
List your "don't do" rules
Things you always have to correct? Write them down. Once.
3
Show one good component example
The AI learns from examples. One good one is worth a lot.
4
Document your folder structure
So new files end up where they belong. Every time.

Why This Little File Makes a Big Difference

Real talk: A good CLAUDE.md can cut your "no, not like that" corrections by 50-70%. That's not hype—it's just what happens when you give context upfront instead of fixing things afterward.

The Four Sections Every CLAUDE.md Needs

You don't need to write a novel. These four sections cover 90% of what your AI needs to know:

1. Project Overview

What does this thing do? Two sentences max. This sets the mental model for everything else.

## Project Overview

TaskFlow is a project management app for remote teams.
Built with Next.js 15 and PostgreSQL. Focus on real-time
collaboration and Slack integration.

2. Commands

What commands does your project use? List them all. The AI will actually use these instead of guessing.

## Commands

```bash
npm run dev          # Start dev server (localhost:3000)
npm run build        # Production build
npm run test         # Run all tests
npm run test:watch   # Tests in watch mode
npm run db:migrate   # Run Prisma migrations
```

3. Architecture

Where does stuff go? This is huge for the AI knowing where to put new files.

## Architecture

### Directory Structure
- `src/app/` - Next.js App Router pages
- `src/components/` - React components
- `src/lib/` - Utilities (no React)
- `src/hooks/` - Custom React hooks
- `src/db/` - Prisma schema and queries

### Key Patterns
- Server Components by default
- Client Components only when needed
- Zustand for client state

4. Coding Standards

The "do this, don't do that" section. Be specific—vague rules get vague results.

## Coding Standards

### Do
- Use TypeScript strict mode
- Write tests for new features
- Keep functions under 50 lines
- Use descriptive variable names

### Don't
- Use `any` type (use `unknown` instead)
- Skip error handling
- Use inline styles (use Tailwind)
- Commit console.logs

Level Up: Advanced Tricks

Show, Don't Just Tell

One good code example beats ten rules. Show what "good" looks like in your project:

### Component Pattern

```tsx
// How we do server/client splits here:
export default async function UserList() {
  const users = await db.user.findMany()
  return <UserListClient users={users} />
}

// UserListClient.tsx - 'use client' at top
```

Point to Key Files

Help the AI find the important stuff quickly:

### Key Files

| File | Purpose |
|------|---------|
| `src/db/schema.prisma` | Database schema |
| `src/lib/auth.ts` | Authentication logic |
| `src/types/index.ts` | Shared type definitions |

Explain Your Domain

The AI doesn't know your business logic. Spell it out:

### Business Logic

- **Workspace**: A team's shared space
- **Project**: A collection of tasks
- **Task**: A unit of work
- Tasks can only be assigned to Workspace members
- Free tier: max 5 members per Workspace

Mistakes That'll Trip You Up

Being Too Vague

"Write clean code" means nothing. "Functions under 50 lines, no nested callbacks deeper than 3 levels" means something.

Writing Too Much

If your CLAUDE.md is 1000 lines, the important stuff gets buried. Aim for under 500 lines. Use bullet points and tables.

Letting It Go Stale

Outdated docs cause more problems than no docs. When you change a pattern, update CLAUDE.md. Seriously.

Skipping Business Context

The AI has no idea what a "workspace" or "subscription tier" means in your app. Explain the concepts.

Start Here (Quick Wins)

Don't have time for everything? These four things give you the biggest bang for your buck:

Add your test command

The AI will run tests after changes if it knows how. Game changer.

List your "don't do" rules

Things you always have to correct? Write them down. Once.

Show one good component example

The AI learns from examples. One good one is worth a lot.

Document your folder structure

So new files end up where they belong. Every time.

CLAUDE.md: How to Make Your AI Actually Understand Your Project

Why This Little File Makes a Big Difference

The Four Sections Every CLAUDE.md Needs

1. Project Overview

2. Commands

3. Architecture

4. Coding Standards

Level Up: Advanced Tricks

Show, Don't Just Tell

Point to Key Files

Explain Your Domain

Mistakes That'll Trip You Up

Being Too Vague

Writing Too Much

Letting It Go Stale

Skipping Business Context

Start Here (Quick Wins)

Skip the Manual Work

CLAUDE.md: How to Make Your AI Actually Understand Your Project

Why This Little File Makes a Big Difference

The Four Sections Every CLAUDE.md Needs

1. Project Overview

2. Commands

3. Architecture

4. Coding Standards

Level Up: Advanced Tricks

Show, Don't Just Tell

Point to Key Files

Explain Your Domain

Mistakes That'll Trip You Up

Being Too Vague

Writing Too Much

Letting It Go Stale

Skipping Business Context

Start Here (Quick Wins)

Skip the Manual Work