Installing and Setting Up Claude Code

Claude Code is a command-line tool, so setup happens in the terminal too. All you need is Node.js installed (Node 18+ is recommended).

Installation

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

Once installed, just go into any project folder and run:

cd my-project
claude

The first time you run it, it will ask you to log in/authenticate — you'll connect your Anthropic account (a Claude subscription or an API key).

What Happens Inside a Project

When Claude Code runs inside a project, it treats that folder as its "working directory" — this is where it reads files, edits them, and runs commands. You can also create a CLAUDE.md file with project-specific instructions (coding conventions, "always run tests before committing") — Claude Code automatically reads this in every session.

# CLAUDE.md

## Project Conventions
- Follow PSR-12 style for PHP
- Always write a Feature test for new features
- Commit messages should follow the conventional commits format

Try Giving It a First Task

> Explore all the controllers in this repo and tell me
> how authentication is being handled.

Starting with a simple, read-only question like this is a good idea — it gives you a sense of how well the agent understands your codebase, without changing anything.

Key Takeaways

• Installation is a single simple npm install -g command.
• Running claude inside a project folder makes it use that folder as context.
• A CLAUDE.md file lets you tell the agent project-specific rules.