The Install

Why this matters

Claude Code is not Claude in a browser. It is an AI agent with file system access, terminal access, and the ability to make changes across your entire codebase in a single session. Installing it and running your first command is the moment you cross from AI user to AI operator. Everything in Modules 1–4 prepared you for what comes next.

How to do it

1. 1

   Install Claude Code globally via npm

   In terminal: npm install -g @anthropic-ai/claude-code — this installs the claude command globally.

2. 2

   Run claude in your project directory

   Navigate to your project: cd ~/path/to/your-app → claude — this opens an interactive session in your terminal.

3. 3

   Authenticate with your API key

   Claude Code will prompt for your Anthropic API key. Get it from console.anthropic.com → API Keys → Create Key. Paste it when prompted.

4. 4

   Run your first command: describe the project

   In the Claude Code session, type: 'What is this project? Describe its structure and main files.' Claude Code will read your entire codebase and respond.

The prompt

What is this project?

Please describe:
1. What the application does
2. The main files and folders and what each is responsible for
3. The technology stack being used
4. The entry point where execution begins
5. Any obvious areas where the code could be improved

Success criteria

• ✓Claude Code is installed and the claude command works
• ✓You authenticated with your API key
• ✓Claude Code described your project accurately
• ✓You understand the difference between Claude.ai (browser) and Claude Code (terminal agent)

Common mistakes