Introduction
Claude Code is Anthropic's terminal-based AI coding agent that goes beyond code completion. It understands your entire codebase, executes multi-file changes, runs tests, and manages git workflows autonomously. This masterclass covers everything from installation to advanced production workflows.
Prerequisites
- Node.js 18+ installed
- Terminal/command line experience
- A project to work with (any language)
- Anthropic API key or Claude Max subscription
Step 1: Installation
bash
# Install globally
npm install -g @anthropic-ai/claude-code
# Verify installation
claude --version
# Start Claude Code in your project
cd your-project
claudeStep 2: Basic Usage
Direct Commands
bash
# Ask Claude to do something
> Add a dark mode toggle to the header
# Fix a specific bug
> Fix the authentication redirect loop in src/auth/callback.ts
# Explain code
> Explain what the middleware in src/middleware.ts doesMulti-File Operations
Claude Code excels at changes spanning multiple files:
bash
> Refactor the database layer to use repository pattern.
Update all services that directly access the database.
# Claude will:
# 1. Read all relevant files
# 2. Create repository interfaces
# 3. Implement repositories
# 4. Update service files
# 5. Update importsStep 3: Project Configuration
Create a CLAUDE.md file in your project root to give Claude context:
markdown
# Project: MyApp
## Tech Stack
- Next.js 15 with App Router
- TypeScript strict mode
- Tailwind CSS
- PostgreSQL with Drizzle ORM
## Conventions
- Use server components by default
- API routes in src/app/api/
- Components in src/components/
- Always write tests for new features
## Commands
- npm run dev - Start dev server
- npm test - Run tests
- npm run lint - Lint codeStep 4: Git Workflow
bash
# Create a feature branch and implement
> Create a branch 'feature/user-profiles' and implement user profile pages
with avatar upload, bio editing, and activity history
# Review changes before committing
> Show me a diff of all changes
# Commit with proper message
> Commit these changes with a descriptive message
# Create a PR
> Create a pull request with a summary of changesStep 5: MCP Integration
Connect Claude Code to external tools via MCP:
json
// .claude/mcp.json
{
"mcpServers": {
"database": {
"command": "node",
"args": ["mcp-servers/database.js"]
},
"jira": {
"command": "node",
"args": ["mcp-servers/jira.js"]
}
}
}Now Claude can query your database and manage Jira tickets directly.
Step 6: Advanced Patterns
Test-Driven Development
bash
> Write tests for the user registration flow first,
then implement the code to make all tests passDebugging
bash
> The /api/payments endpoint returns 500. Debug it by:
1. Reading the error logs
2. Checking the Stripe integration
3. Fixing the issue
4. Adding error handlingTroubleshooting
- Claude doesn't understand the project: Add a CLAUDE.md with context
- Changes break things: Ask Claude to run tests after each change
- Slow responses: Use a smaller context by being specific about which files to read
- API errors: Check your API key and usage limits
Conclusion
Claude Code transforms the terminal into a powerful AI-assisted development environment. By combining CLAUDE.md configuration, MCP integrations, and effective prompting, you can achieve remarkable productivity gains.
Key Takeaways
- Always create a CLAUDE.md for project context
- Use multi-file operations for complex refactoring
- Integrate MCP for external tool access
- Review changes before committing