Claude Code Series, Part 1: Getting Started

Installation

Claude Code requires Node.js 18+. Install it globally via npm:

npm install -g @anthropic-ai/claude-code

Verify the installation:

claude-code --version

API Key Setup

Claude Code communicates with Claude via the Anthropic API. You’ll need an API key from console.anthropic.com.

Sign up or log in at Anthropic’s console
Navigate to API Keys
Create a new API key
Copy it and set it as an environment variable:

export ANTHROPIC_API_KEY="sk-ant-..."

To make this permanent, add it to your shell profile (~/.zshrc, ~/.bashrc, etc.):

echo 'export ANTHROPIC_API_KEY="sk-ant-..."' >> ~/.zshrc
source ~/.zshrc

Your First Session

Open a terminal in any project directory and start Claude Code:

claude-code

You’ll see an interactive prompt. Try something simple first:

You: "List the main files in this project"

Claude will read your directory structure and respond. If it wants to run a command (like ls or cat), it will ask for permission first:

[Tool Use: Bash]
Command: ls -la
Ready to execute? (y/n)

Approve with y and watch Claude work.

Key Mental Models

1. Claude reads your entire codebase

Unlike Copilot (which sees only the current file), Claude Code automatically scans your project. It understands:

Your file structure
Language and framework (React, Python, Rust, etc.)
Common patterns and naming conventions
Dependencies and imports

This means you can ask it to “add a button to the login form” and it will find the login form, understand the styling system, and make changes that match your codebase’s patterns.

2. You’re the decision maker

Claude Code never does anything destructive without your approval. When it needs to:

Delete files
Run commands
Make commits
Force-push to git

…it stops and waits for you to say yes or no. Read the proposed action carefully before approving.

3. Multi-turn conversations

Claude Code sessions are stateful. Previous messages inform future responses. You can refine requests:

You: "Add a loading spinner to the button"
Claude: [Makes changes]
You: "Make it spin faster"
Claude: [Refines the animation]

Basic Commands

Here are common things to ask Claude Code:

Code exploration

“Show me how authentication works in this codebase”
“What does the [function name] function do?”
“Find all usages of [class name]“

Bug fixes

“Fix the error: [error message]”
“Why is this test failing?”
“Refactor this function to be cleaner”

Feature addition

“Add a search bar to the homepage”
“Implement error handling for the API call”
“Create a dark mode toggle”

Testing & documentation

“Write tests for [component]”
“Generate API documentation”
“Add comments to this function”

Exiting Claude Code

Press Ctrl+C to exit or type:

/exit

Your conversation history is saved locally, so you can resume it later (or start fresh).

Next Steps

Now that you’re set up, the next post dives into hooks — how to automate workflows, enforce project rules, and get notified when Claude needs input.

Next: Part 2 — Hooks — Automate Workflows