Setting Up Claude Code
Like a Professional

• Install and configure VS Code, Claude Code, Git, Node.js and Python correctly on Mac, Windows or Linux.
• Understand the terminal well enough to move around, create files, and run commands without fear.
• Create Anthropic and OpenRouter API keys and store them safely with environment variables.
• Design a clean, professional folder layout for every future project.
• Ship your first working Claude Code project end-to-end.

Visual Studio Code (VS Code) is a free, fast, extensible code editor from Microsoft. It is the industry-standard editor for AI development, and Claude Code plugs into it beautifully.

Step-by-step install

1. Open code.visualstudio.com in your browser.
2. Click the big download button — the site auto-detects your operating system.
3. Open the installer, accept the defaults, and launch VS Code once it finishes.
4. On Mac, also run Shell Command: Install 'code' command in PATH from the Command Palette (Cmd+Shift+P).

Claude Code ships as a command-line tool you run from your terminal. It reads and edits files in whatever folder you launch it from — that folder becomes your workspace for the session.

# macOS or Linux
curl -fsSL https://claude.ai/install.sh | sh

# Windows (PowerShell)
irm https://claude.ai/install.ps1 | iex

# Verify
claude --version

The first time you run claude, you will be asked to log in with your Anthropic account or an API key. Either works; we will set up an API key in section 8 for automation.

Git is the time-machine of software. It records every change you make so you can undo, branch, and collaborate safely. When you let an AI edit your code, Git is your seatbelt.

# Install (macOS)
brew install git
# Install (Windows) — use git-scm.com installer
# Install (Ubuntu)
sudo apt install git

# Configure once
git config --global user.name "Your Name"
git config --global user.email "you@example.com"

# Basic loop
git init          # start tracking a folder
git add .         # stage changes
git commit -m "message"   # save a snapshot
git log --oneline # see history

GitHub is a cloud home for your Git repositories. It gives you backup, collaboration, portfolio, and — in later chapters — deployment triggers. Create a free account at github.com.

1. Sign up with a professional-looking username.
2. Create a new empty repository called claude-code-playground.
3. Follow the "push an existing repository" snippet GitHub shows you.

git remote add origin https://github.com/<you>/claude-code-playground.git
git branch -M main
git push -u origin main

Node.js runs JavaScript outside the browser. You will use it for the web-app chapters and for many AI SDKs. Install the LTS version.

# macOS
brew install node
# Windows — nodejs.org installer, "LTS" option
# Ubuntu
sudo apt install nodejs npm

node --version
npm --version

Python is the lingua franca of AI. Most agent frameworks, notebooks, and research libraries live here. Install Python 3.11 or newer.

# macOS
brew install python@3.12
# Windows — python.org installer, TICK "Add Python to PATH"
# Ubuntu
sudo apt install python3 python3-venv python3-pip

python3 --version
pip3 --version

The terminal is where Claude Code lives. You do not need to memorize hundreds of commands — ten will take you 80% of the way.

pwd            # where am I?
ls             # what's in this folder?
cd projects    # move into a folder
cd ..          # up one folder
mkdir demo     # make a new folder
touch app.py   # create an empty file
cat app.py     # print file contents
rm app.py      # delete the file
clear          # clear the screen
history        # what did I just run?

For anything programmatic, you need an Anthropic API key. This is what gives your code the right to talk to Claude.

1. Go to console.anthropic.com and sign up.
2. Add billing (a few dollars is enough to build every project in this book).
3. Open API Keys → Create Key, name it handbook-dev, and copy the value.
4. Paste it into your .env file as ANTHROPIC_API_KEY.

OpenRouter is a single API that fronts dozens of AI models — Claude, GPT, Gemini, Llama, and more. It is invaluable when you want to compare models or fall back automatically.

1. Sign up at openrouter.ai.
2. Top up $5 of credits.
3. Generate a key and store it as OPENROUTER_API_KEY.

An .env file is a plain text file where you keep secrets, one per line. Your app reads them at runtime, so the secrets stay out of Git.

ANTHROPIC_API_KEY=sk-ant-xxxxxxxxxxxx
OPENROUTER_API_KEY=sk-or-xxxxxxxxxxxx
NODE_ENV=development

# .gitignore  <-- add this line so secrets never reach GitHub
.env

A predictable folder layout lets Claude Code find things quickly and lets future-you understand past-you. Use this template for every new project:

my-project/
├─ .env                # secrets (ignored by git)
├─ .gitignore
├─ README.md           # what & why
├─ CLAUDE.md           # notes to the AI (repo conventions)
├─ src/                # your code
│  ├─ index.ts
│  └─ lib/
├─ prompts/            # reusable prompt templates
├─ scripts/            # one-off automation
├─ tests/
└─ docs/

• Prettier — automatic formatting.
• ESLint — catches JavaScript mistakes.
• Python (Microsoft) — Python language support.
• GitLens — supercharged Git in VS Code.
• Error Lens — surfaces errors inline while you type.
• Docker — for the deployment chapter.
• Even Better TOML — for config files.

1. One folder per project — never mix two apps in one repo unless it is a monorepo.
2. Write a one-paragraph README.md before you write any code.
3. Keep secrets in .env, config in config/, and content in content/.
4. Commit little and often — small commits are easy to review and easy to undo.

Open a new terminal, cd into your empty project folder, and run:

claude "Create a Python script that prints the first 20 Fibonacci numbers,
save it as fib.py, then run it and show me the output."

Notice how Claude Code broke the request into steps: create → run → report. That is the loop from Chapter 1 in the wild.

Let us build a tiny Markdown-to-HTML converter, entirely through Claude Code.

mkdir md2html && cd md2html
git init
claude "Set up a Node.js project called md2html using TypeScript.
Add a single command 'convert' that takes a .md file and writes a styled .html file
in the same folder. Include a nice CSS theme, a README, and one test file.
Then run the test to prove it works."