Level 1: User — Master CLAUDE.md and Basic Commands

The reason people get stuck at Level 0 is that Claude is operating with no knowledge of the project’s context. Just by creating a CLAUDE.md, Claude Code starts up already understanding the project’s structure, tech stack, and coding conventions. That’s the core of Level 1.

Target audience: Anyone who has Claude Code installed and wants to use Claude seriously in their project.

Estimated learning time: Read 15min + Practice 20min

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What Is CLAUDE.md?

CLAUDE.md is a configuration file that Claude Code automatically reads every time you open a project. By writing your project overview, tech stack, and coding conventions here, you never have to explain them again each session.

What to Write in CLAUDE.md

Item	What to write	Example
Project overview	What you’re building · purpose	”A REST API server built with Python + FastAPI”
Tech stack	Language · framework · key libraries	Python 3.11, FastAPI, SQLAlchemy, PostgreSQL
Directory structure	Role of key folders	src/routes/ — endpoint definitions
Coding conventions	Naming rules · comment rules, etc.	”Always write type hints” “Comments in English”
Common commands	Development · testing · build commands	uvicorn main:app --reload

CLAUDE.md Template

Here is a template using a Python + FastAPI project as an example:

# Project Name

A REST API server built with Python + FastAPI.
Provides user management, authentication, and data retrieval features.

## Tech Stack

- Language: Python 3.11
- Framework: FastAPI
- ORM: SQLAlchemy
- Database: PostgreSQL
- Testing: pytest
- Deploy: Docker + AWS ECS

## Directory Structure

- `src/routes/` — endpoint definitions (routers)
- `src/models/` — SQLAlchemy models
- `src/schemas/` — Pydantic schemas
- `src/services/` — business logic
- `tests/` — pytest test files

## Coding Conventions

- Always write type hints (arguments and return values)
- Write comments in English
- Add docstrings to all endpoints
- Function and variable names use snake_case

## Common Commands

- Start dev server: `uvicorn src.main:app --reload`
- Run tests: `pytest tests/ -v`
- Type check: `mypy src/`
- Format code: `ruff format src/`

Where to Place CLAUDE.md

CLAUDE.md can be placed in multiple locations:

your-project/
├── CLAUDE.md          ← Applied to the entire project
├── src/
│   ├── routes/
│   │   └── CLAUDE.md  ← Applied only to this directory (optional)
│   └── models/
└── tests/
    └── CLAUDE.md      ← Rules specific to the test directory (optional)

The root CLAUDE.md applies to the whole project. A CLAUDE.md placed in a subdirectory is loaded additionally only within that directory. This is useful when you want to manage test-writing rules or module-specific rules separately.

Basic Command Reference

Key commands available inside Claude Code.

Command	Description
/help	Show a list of available commands
/clear	Reset conversation history (empty the context window)
/memory	Check currently loaded memory (CLAUDE.md, etc.)
/quit or Ctrl+C	Exit Claude Code

Try It: Create a CLAUDE.md and Verify with /memory

1. Create CLAUDE.md at the root of your project
2. Write the project overview, tech stack, and common commands
3. Launch Claude Code and run /memory

cd your-project
claude

Inside Claude Code:

/memory

Example output:

## Project Memory (CLAUDE.md)
# Project Name
A REST API server built with Python + FastAPI.
...

If the contents of CLAUDE.md are displayed, Claude is running with an understanding of your project.

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Hands-On Tutorial

If you want to learn by doing, check out the tutorial.

Hands-on tutorial for this level →

Next Level

Level 2: Integrator — Connect Tools with MCP