Claude Code CLI Headless Mode
Introduction to Claude Code CLI
Your Coding Assistant in the Terminal
Most developers spend their day in two places: a code editor and a terminal. The terminal, or command-line interface (CLI), is a text-based way to run programs and manage your computer. Instead of clicking on icons, you type commands.
Claude Code brings the power of an AI assistant directly into this workflow. It’s a CLI tool that lets you chat with Claude without ever leaving your terminal.
Claude Code is Anthropic’s agentic coding CLI — a terminal-first tool that connects your development environment to Claude models so the assistant can read your repo, run commands, edit files, run tests, create commits, and execute multi-step workflows from the terminal.
This means you can ask Claude to write code, debug an error, or even explain a complex file, all from the same window where you run your development server or manage your code with Git. It's about staying focused and making your workflow smoother.
Installation
Getting Claude Code set up is straightforward. The main prerequisite is having Node.js installed on your system. Claude Code requires version 16 or higher. You can check your version by opening your terminal and typing:
node -v
If you see a version number like v18.17.0 or higher, you're good to go. If not, you'll need to install or update Node.js first.
Once Node.js is ready, you can install Claude Code globally on your machine using the Node Package Manager (npm). This makes the claude command available from anywhere in your terminal.
npm install -g @anthropic-ai/claude-code-cli
After the installation finishes, you need to log in to your Anthropic account to authenticate the CLI.
claude login
This command will open a browser window for you to sign in. Once you've done that, your terminal is connected to your account and ready for action.
Basic Commands
To start an interactive chat session, navigate to your project's directory in the terminal and simply run the claude command.
claude
This drops you into a chat interface right in your terminal. You can now talk to Claude just like you would on the web. For example, you could ask it to create a simple function.
Write a Python function that takes a list of numbers and returns the sum.
Claude will respond with the code and an explanation. Because you started Claude Code from your project directory, it has context about the files around it. You can ask it to read a specific file and explain it, or even suggest improvements.
To end the interactive session, just type .quit or press Ctrl+C.
Time to check your understanding of these first steps.
What is the primary purpose of the Claude Code CLI tool?
What is the minimum version of Node.js required to install and run Claude Code?
Now that you're set up, you can start integrating Claude into your daily coding tasks right from the command line.