Getting Started with Claude Code

Install, configure, and start using Claude Code for real work in 5 minutes.

What is Claude Code?

Claude Code is Anthropic's official CLI tool that puts Claude directly in your terminal. It can read and edit files, run commands, search codebases, create commits, manage pull requests, and handle complex multi-step engineering tasks. Think of it as a senior engineer pair-programming with you.

Install

1 Install via npm

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

Requires Node.js 18+. Alternatively, download the desktop app for Mac or Windows.

2 Authenticate

Run claude in your terminal. It will open a browser window to authenticate with your Anthropic account on first launch.

claude

3 Start Using It

Navigate to any project directory and launch Claude Code:

cd my-project
claude

Then just type what you want. Examples:

"Fix the failing test in auth.test.ts"
"Add a dark mode toggle to the settings page"
"Explain how the payment flow works"
"Find all API endpoints that don't have rate limiting"

Key Concepts

CLAUDE.md

Drop a CLAUDE.md file in your repo root to give Claude persistent context about your project: build commands, architecture decisions, coding conventions, things to avoid. Claude reads it automatically every session.

# CLAUDE.md

## Build
npm run build && npm test

## Rules
- Use TypeScript strict mode
- No default exports
- Tests go in __tests__/ next to source

Slash Commands

Type / to see available commands:

/help — see all commands
/compact — compress conversation context
/clear — start fresh
/fast — toggle fast mode (same model, faster output)

Plugins & MCP Servers

Claude Code supports MCP (Model Context Protocol) servers that extend its capabilities. Plugins can add integrations like iMessage, Slack, databases, and more.

/install-plugin imessage

See the iMessage setup guide for a full walkthrough.

Tips

Be specific

"Fix the bug where users can't log in after password reset" beats "fix the login bug".

Let it read first

Claude will read relevant files before making changes. If it's heading in the wrong direction, just say so — it course-corrects well.

Use it for research

"How does the caching layer work?" or "What would break if I removed this middleware?" — Claude can explore your codebase and explain what it finds.

Commit from Claude

Ask "commit these changes" and Claude will stage, write a good commit message, and commit. It follows your repo's commit style.