🤫 The Secret `.md` File That Doubles Your AI Coding Speed

Source: Dev.to

Stop repeating yourself.

If you type “Please use TypeScript and Tailwind” at the start of every chat, you’re doing AI development wrong.

We’ve all been there: you open a fresh chat with Claude 3.5 Sonnet (or ChatGPT), paste in an error log, and the AI confidently suggests a fix… in Python.
Your project is in Rust, so you correct it. Then it gives you a Rust fix, but uses an outdated library. After a few back‑and‑forth exchanges you’ve wasted minutes and thousands of tokens.

There’s a better way. The team at Builder.io uses a simple trick—a “Context Cheat Sheet” for your LLM—called the CLAUDE.md file.

What is CLAUDE.md?

Think of CLAUDE.md as a README for Robots.
Your regular README.md is for humans, full of badges and marketing copy.
Your CLAUDE.md is for the AI: dense, factual, and containing exactly what the model needs to start coding immediately. When you attach (or paste) this file at the start of a session, the AI gains “Senior Engineer”‑level context about your repository.

The Perfect CLAUDE.md Template

Based on Builder.io’s guide, a high‑performance context file should contain four distinct sections.

1. Build & Run Commands

Tell the AI explicitly how to start, test, and build your project.

## Commands
- Run Dev: `npm run dev`
- Run Tests: `npm test`
- Build: `npm run build`
- Database: `docker-compose up -d db`

2. Coding Standards (The “No‑Go” Zone)

Prevent the AI from using bad patterns.

## Code Style
- Use TypeScript for all new files.
- Prefer functional components over class components.
- Styling: Use Tailwind CSS utility classes (no CSS modules).
- State Management: Use Zustand, DO NOT use Redux.
- Error Handling: Use try/catch blocks in all async functions.

3. Architecture Overview

Give the AI a mental map of your project structure.

## Architecture
- /src/components: Reusable UI atoms.
- /src/features: Domain‑specific business logic.
- /src/hooks: Custom React hooks.
- **Rule**: Business logic should NEVER exist inside UI components. Move it to a custom hook.

4. Tech Stack Definition

List every major library so the AI doesn’t hallucinate imports.

## Tech Stack
- Frontend: Next.js 14 (App Router)
- UI: Shadcn UI + Lucide Icons
- DB: Supabase
- Auth: Clerk

Why This Changes Everything

When you feed this file to Claude at the start of a session (or add it to your “Project Knowledge” in Claude Projects), three things happen:

• Zero‑Shot Accuracy: The AI immediately writes code that fits your style—no need to convert const to var or add missing types.
• Less Hallucination: Explicit library listings stop suggestions like installing axios when you already use fetch.
• Onboarding Aid: New developers can read CLAUDE.md to grasp strict technical guidelines without the fluff.

Automating the Context Injection

You can automate copying the file to your clipboard. Create a script copy-context.sh:

# macOS / Linux
cat CLAUDE.md | pbcopy
echo "Context copied to clipboard!"

Run ./copy-context.sh, paste into Claude, and say something like “Let’s refactor the login component.” It just works.

The Future: .ai Files?

We’re moving toward AI‑Native Repositories. Just as we have .gitignore for Git and .dockerignore for Docker, every repo will soon need a configuration file specifically for AI agents.

Whether you call it .cursorrules, CLAUDE.md, or context.txt, the principle is the same: Context is King.

Create a CLAUDE.md in your current project today—you’ll thank yourself later.