Configure Claude Code the right way.
Real CLAUDE.md files, setup guides, and comparisons — written by devs who actually ship. Avoid the noise and build robust context.
What are you looking to do?
Select your current stage to find target guidelines and templates.
I'm new to Claude Code
Start with the high-level explanations. Understand how Anthropic's terminal agent processes files, runs builds, and stores configurations.
I want CLAUDE.md for my stack
Copy production-grade rules and setups built specifically for modern frameworks. Complete with commands, exclude patterns, and styling rules.
I'm comparing AI rules
Learn how Anthropic's CLAUDE.md specifications compare to Cursor rules and traditional AGENTS.md conventions. Decide which layout fits your team.
The Complete Guide to CLAUDE.md Files
Everything you need to know about configuring Anthropic's Claude Code with claude.md best practices, templates, and real-world examples.
CLAUDE.md is the configuration file Anthropic's Claude Code CLI reads at startup to understand your project. It stores the build commands, test scripts, coding conventions, and architectural rules the agent needs to work on your codebase — so it can build, test, and refactor without guessing your setup on every session.
Whether you call it claude.md, CLAUDE.md, or claude md file, this markdown configuration document is the single most important file you can create when adopting Claude Code for your development workflow. Unlike traditional IDE configuration files that focus on editor behavior, the CLAUDE.md file is purpose-built for terminal-native AI agents. It provides explicit instructions for building, testing, linting, and structuring your codebase, allowing Claude Code to operate as a fully autonomous engineering teammate rather than a guessing chatbot.
What is CLAUDE.md and Why Does It Matter?
A CLAUDE.md file is a plain text markdown document placed in your project's root directory that tells Claude Code exactly how your project works. It answers critical questions: How do I build this project? What test framework is used? What are the code style rules? Where are components stored? Without this file, Claude Code must search your directory structure, parse configuration files, and make educated guesses about your conventions. With it, the agent starts every session with perfect context about your architecture, coding standards, and build pipeline.
The lesson the community has converged on: keep CLAUDE.md short and command-focused. Every line is appended to Claude Code's system prompt on every turn, so verbose files inflate your token bill without helping the agent. A good CLAUDE.md is closer to a Makefile with comments than a project README.
CLAUDE.md Best Practices
Following claude md best practices ensures your configuration delivers maximum value while minimizing token consumption. Here are the essential guidelines for crafting an effective CLAUDE.md file:
- Keep it under 150 lines: Every line of your claude.md file is appended to the system prompt on every turn. Concise files reduce latency and token costs.
- Prioritize commands over explanations: Include exact build, test, lint, and dev server commands. Claude Code is a terminal tool — it needs precise CLI strings, not paragraphs of context.
- Structure with clear headings: Use markdown headings to separate build commands, style guidelines, architectural rules, and project conventions. This makes the file scannable for both humans and AI.
- Be specific with directory paths: Tell Claude exactly where components, utilities, and pages live. This prevents the agent from searching your entire project tree.
- Update regularly: Outdated commands are worse than no commands. If a build script changes but your CLAUDE.md doesn't, Claude will waste tokens debugging the wrong configuration.
The claude md file best practices landscape has been shaped by the broader AI engineering community. Engineers who adopt these patterns report significantly fewer API token overruns, faster task completion, and more consistent code generation across sessions.
CLAUDE.md Templates by Framework
One of the most powerful aspects of the CLAUDE.md ecosystem is the availability of claude.md examples and templates for popular frameworks. Whether you need a claude.md nextjs template for your App Router project, a claude.md react configuration for your SPA, or a claude.md dotnet setup for your ASP.NET Core Web API, having a proven starting point dramatically reduces configuration time. Each template includes framework-specific build commands, test patterns, lint rules, and directory conventions that match the standard tooling for that ecosystem.
Our claude.md examples section provides ready-to-use templates for Next.js App Router, React with TypeScript, and ASP.NET Core Web API. Each includes exact commands for building, testing, and running the development server, plus code style guidelines specific to the framework's conventions.
CLAUDE.md vs AGENTS.md: Understanding the Difference
A common question among developers is the difference between CLAUDE.md vs AGENTS.md. While both files serve as AI configuration documents, they target fundamentally different tools and use cases. CLAUDE.md is explicitly designed for Anthropic's Claude Code CLI — a terminal-native agent that builds, tests, and modifies code directly in your repository. It prioritizes executable commands and build workflows. AGENTS.md, by contrast, is an IDE-agnostic convention used by editor-based agents like Cursor, Windsurf, and other code editor extensions. It focuses more on directory structure, styling preferences, and general coding guidelines rather than specific CLI commands.
Understanding this distinction is crucial for teams using multiple AI tools. You can safely use both files in the same repository without conflicts — CLAUDE.md for terminal operations and AGENTS.md for editor integrations. This claude.md vs agents.md harmony allows you to optimize each configuration for its specific runtime environment.
Claude Code Memory and CLAUDE.md
Claude code memory is a related concept that complements your CLAUDE.md configuration. While CLAUDE.md provides static, file-based rules that are read at startup, Claude Code also maintains dynamic memory through its .claude/ directory, which stores learned information about your project across sessions. Skills, MCP server configurations, and settings.json files all contribute to the agent's persistent understanding of your workflow.
Understanding how claude code memory claude.md official docs recommend combining these elements is key to building a robust AI-assisted development environment. The static CLAUDE.md file provides the foundation, while dynamic memory layers adapt to your evolving project structure over time.
How to Write a CLAUDE.md File
Learning how to write claude.md is straightforward. Start with a simple template that includes build and test commands, then expand with code style guidelines and architectural rules as your project grows. A minimal claude.md template might look like this:
# Build & Test Build: npm run build
Test: npm test
Lint: npm run lint
Dev: npm run dev
# Code Style - TypeScript strict mode
- React functional components
- Tailwind CSS for stylingFrom this foundation, you can layer in framework-specific commands, exclude patterns for directories Claude should not modify, and project conventions that match your team's engineering standards. The claude md template approach ensures consistency across projects and makes onboarding new repositories trivial.
Frequently Asked Questions
Everything you need to know about CLAUDE.md files and Claude Code setup.
What is a CLAUDE.md file for?
A CLAUDE.md file is a configuration document for Anthropic's Claude Code CLI. Its purpose is to store project guidelines, build commands, test scripts, coding style rules, and directory conventions. By providing this context, Claude Code can instantly understand your project architecture without searching your file tree, saving API tokens and reducing latency. It acts as the bridge between your codebase and the AI assistant.
What is CLAUDE.md vs. SKILL.md?
CLAUDE.md is a static configuration file that sets project-wide rules, commands, and guidelines read at startup. SKILL.md (or Skills) are executable scripts stored in the .claude/skills/ directory that Claude Code can run autonomously to perform complex multi-step tasks like database migrations, code reviews, or deployments. CLAUDE.md defines how your project works; Skills define what Claude Code can do on your behalf.
Is CLAUDE.md really useful?
Yes. Without a CLAUDE.md file, Claude Code must guess your project layout, search for package files, infer test commands, and make assumptions about your coding standards. This wastes API tokens, increases latency, and produces inconsistent results. A well-written CLAUDE.md eliminates all of this — the AI starts every session with perfect context about your build pipeline, directory structure, and code conventions, resulting in faster, more accurate outputs.
What does CLAUDE.md management do?
CLAUDE.md management refers to the practice of maintaining, organizing, and version-controlling your CLAUDE.md files across projects. This includes deciding which rules go into the global ~/.claude/CLAUDE.md file versus per-project root files, keeping files under recommended size limits, updating commands when build tools change, and structuring rules for maximum AI comprehension. Good management ensures consistent AI behavior across your entire development workflow.
Is MD file safe?
Yes. CLAUDE.md files are plain text markdown documents with no executable code. They contain only human-readable instructions, command strings, and configuration rules. There is no risk of executing malicious scripts, as Claude Code reads the file as a text-based guideline — it does not execute the markdown content directly as code. Standard markdown security practices apply: review commands before adding them.
Is CLAUDE better than ChatGPT?
CLAUDE.md and ChatGPT serve different purposes. CLAUDE.md is a configuration file format for Anthropic's Claude Code — a terminal-native AI assistant that builds, tests, and modifies code directly in your repository. ChatGPT is a general-purpose conversational AI. Claude Code excels at autonomous software engineering tasks like running builds, executing tests, and refactoring codebases, while ChatGPT is better suited for general Q&A and content generation.
Is CLAUDE.md hierarchical?
Yes, CLAUDE.md supports hierarchical nesting. You can place a root CLAUDE.md in your project root directory and additional CLAUDE.md files in subdirectories. Subdirectory rules inherit settings from the parent file but can override them for scoped modules. This is particularly useful for monorepos where different packages have different build commands, test frameworks, or coding conventions. Claude Code respects directory nesting and merges rules appropriately.
Is CLAUDE.md required?
CLAUDE.md is not technically required — Claude Code will function without it by searching your project structure and making inferences. However, it is strongly recommended for production use. Without it, the AI wastes significant context window capacity on discovery tasks, produces less consistent code, and frequently asks clarifying questions. Most experienced users consider CLAUDE.md essential for reliable, efficient AI-assisted development.
Do I need both AGENTS.md and CLAUDE.md?
You do not need both, but you can safely use them in the same repository without conflicts. CLAUDE.md is designed for Anthropic's Claude Code CLI. AGENTS.md is a broader convention used by editor-integrated agents like Cursor. If you use only Claude Code, CLAUDE.md is sufficient. If you use multiple AI tools, having both files lets you optimize each configuration for its specific runtime environment.
Is CLAUDE.md per project?
CLAUDE.md is typically per project, placed in the workspace root of each repository. However, you can also create a global CLAUDE.md at ~/.claude/CLAUDE.md that applies across all projects. The resolution order is: global settings.json, then global CLAUDE.md, then project-level CLAUDE.md. Project-level rules override global ones for conflicting directives, giving you per-project flexibility with global defaults.
How big should CLAUDE.md be?
Keep your CLAUDE.md under 150 lines for most projects, with an absolute maximum of 300 lines for large repositories. Every line is appended to the system prompt on every message turn, so larger files increase token consumption, API latency, and cost. Focus on essential build commands, test instructions, and critical code style rules. Avoid narrative explanations, lengthy examples, or obvious conventions that the model already understands.
What is the best CLAUDE.md?
The best CLAUDE.md is concise, command-focused, and framework-specific. It includes exact CLI strings for building, testing, linting, and running the dev server. It specifies directory conventions, coding standards, and file naming patterns. It avoids prose and boilerplate. Popular templates include Andrej Karpathy's minimalist approach and Boris Cherny's structured formatting. The right CLAUDE.md for your project depends on your stack — Next.js, React, and .NET each benefit from framework-specific templates.
How should I setup Claude Code?
To setup Claude Code, install Node.js v22.12+ and run: npm install -g @anthropic-ai/claude-code. Then run claude in your terminal to authenticate via your Anthropic account. After authentication, navigate to your project directory and run claude again. Create a CLAUDE.md file in your project root with build and test commands. Optionally configure ~/.claude/settings.json for theme, editor, auto-approve, and max tokens preferences. For IDE integration, use VS Code or Cursor with the Claude extension.
How do I setup Claude Code for free?
Claude Code itself is free to install via npm, but it requires an Anthropic API key with available credits to function. New accounts receive free credit grants that allow experimentation. You can also use Claude Code locally without cost by signing up for Anthropic's free tier. For ongoing free usage, consider using Claude Code's limited mode for smaller projects or monitoring Anthropic's pricing page for free tier updates.
How do I build my own Claude Code?
You cannot build your own Claude Code — it is a proprietary tool developed and distributed by Anthropic. However, you can extend its functionality through Skills (custom scripts in .claude/skills/), MCP servers (connecting to external tools and APIs), and meticulously crafted CLAUDE.md files. These customization options let you tailor Claude Code's behavior to your exact workflow without modifying the core tool.
How do I set up Claude Code on Anthropic?
Setting up Claude Code on Anthropic involves: (1) Creating an account at console.anthropic.com, (2) Ensuring you have API credits or a paid plan, (3) Installing the CLI globally via npm install -g @anthropic-ai/claude-code, (4) Running claude to trigger the OAuth handshake with Anthropic's servers, and (5) Entering the verification code displayed in your terminal. Your credentials are then stored locally in ~/.claude/ for future sessions.
Can I run Claude Code directly in my terminal?
Yes. Claude Code is a terminal-native tool designed to run directly in your command line interface. After installation, simply run claude in any project directory to start a session. It supports macOS, Linux, and Windows through WSL. The CLI provides an interactive interface where you can ask questions, request code changes, run commands, and manage files — all within your terminal without needing a separate GUI application.
Is there a GitHub repository for Claude Code?
Claude Code is distributed as a private npm package by Anthropic and does not have a public GitHub source repository. However, Anthropic maintains official documentation and issue tracking through their developer portal. The community has created various open-source resources, CLAUDE.md templates, and setup guides (like this site) that are available on GitHub to help users configure and optimize their Claude Code experience.
Can I run Claude Code locally for free?
Claude Code runs entirely on your local machine — the CLI executes in your terminal, processes files locally, and only sends API requests to Anthropic's servers for AI inference. The tool installation is free via npm. However, each API request consumes credits from your Anthropic account. New users receive free credits, but sustained usage requires a paid plan. Using a well-optimized CLAUDE.md reduces API calls, making your credits last significantly longer.