CLAUDE.md is the single file that shapes how Claude understands your project. A well-written one means fewer corrections, better code, and agents that actually know what they're working on.
This guide walks you through every section of a CLAUDE.md file, from tech stack declarations to agent-specific hints. Follow along and build yours step by step.
CLAUDE.md is a markdown file you place at the root of your project. When Claude Code starts a session, it reads this file first. Everything inside it becomes part of Claude's context: your tech stack, your file structure, your team's conventions, and any specific instructions you want every agent to follow.
Think of it as a briefing document. Without it, Claude has to guess how your project is organized. With a good one, Claude already knows where things live, which patterns to follow, and what to avoid. The difference in output quality is significant.
“A 10-minute investment in CLAUDE.md saves hours of correcting AI-generated code that doesn't match your project's patterns.”
Observed across hundreds of Claude Code projects
The structure and specificity of your CLAUDE.md directly impacts how well Claude performs in your codebase.
A well-structured CLAUDE.md covers these six areas. Each one gives Claude concrete information it can act on immediately.
List your frameworks, libraries, and their versions explicitly. Include your package manager, Node version, and any runtime requirements. Claude uses this to generate compatible code without guessing.
Describe your key directories and what lives in each one. Components, stores, services, API routes, types. A short tree diagram with one-line descriptions per folder works well.
Document your naming patterns (camelCase for files, PascalCase for components), error handling approach, import ordering, and any project-specific rules. This keeps Claude's output consistent with your existing code.
Include your dev, build, test, and lint commands. When Claude needs to verify something works or suggest a script, it will use the exact commands your project expects.
If you use multiple agents (QA, frontend, backend, DevOps), add a section describing what each role should focus on. This is especially useful with AgentsRoom's multi-agent setup.
Tell Claude what NOT to do. Don't modify config files, don't change the auth system, don't refactor the database layer. Explicit boundaries prevent agents from making unwanted changes.
You don't need to write everything at once. Start with the basics and expand as you discover what Claude needs to know.
Open your package.json and list every framework, library, and tool your project uses. Note the versions. Check your runtime requirements (Node version, Python version, database). This becomes your tech stack section.
package.json + runtime versions + database
Run a quick tree of your src directory. Identify the top-level folders and write a one-line description of each. Focus on where components, stores, services, types, and API routes live.
src/ tree with purpose annotations
Look at your existing code and note the patterns: how you name files, how you handle errors, how you structure imports, whether you use default or named exports. Write these down as short rules.
Naming, imports, error handling, exports
If you work with specialized agents, add focus areas for each role. The frontend agent should know your component library. The DevOps agent should know your deployment pipeline. The QA agent should know your testing framework.
Per-role focus areas + avoid areas
AgentsRoom is built around CLAUDE.md as a first-class concept, not an afterthought.
Edit your CLAUDE.md directly inside AgentsRoom with syntax highlighting and live saving. No switching to your text editor or IDE.
See how each agent interprets your CLAUDE.md in real time. Watch terminal output to verify that agents follow your conventions and respect your avoid areas.
Each project in AgentsRoom has its own CLAUDE.md. Switch between projects and each agent automatically loads the right context file for that codebase.
AgentsRoom's 14 agent roles pair directly with CLAUDE.md sections. Define focus areas and avoid areas per role, and each agent picks up exactly the instructions meant for it.
Download AgentsRoom and use the built-in CLAUDE.md editor to give your agents the context they need. Better instructions, better code.
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