Learn

Claude Code Quickstart

Get Claude Code running in your project in 5 minutes.

Install

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

Requires Node.js 18+ and an Anthropic API key (or Claude Pro/Team subscription).

First Project

cd my-project
claude

Claude reads your project structure and any CLAUDE.md file, then waits for your prompt.

Try something simple:

> What does this project do? Give me a one-paragraph summary.

Claude will read key files (README, package.json, main entry points) and respond.

Write a CLAUDE.md

Create a CLAUDE.md at your project root. This is the single most impactful thing you can do to improve Claude Code’s behavior:

# My Project

## Build & Test
- `npm run build` to compile
- `npm test` to run tests
- `npm run lint` to check style

## Architecture
- src/api/ - REST endpoints (Express)
- src/db/ - Database queries (Postgres via pg)
- src/services/ - Business logic

## Conventions
- Use TypeScript strict mode
- Prefer named exports
- Error handling: throw AppError with status codes
- Tests: colocate with source files as *.test.ts

Claude reads this at session start and follows it throughout.

Key Commands

CommandWhat it does
/helpList all commands
/clearReset conversation context
/compactCompress context (useful for long sessions)
Cmd+KTopic switcher - jump between separate task threads
Esc EscUndo last change (restore checkpoint)
/rewindRewind to a specific checkpoint

Configure Permissions

By default, Claude asks before editing files or running commands. Speed this up by allowing common operations in .claude/settings.json:

{
  "permissions": {
    "allow": [
      "Bash(npm test)",
      "Bash(npm run build)",
      "Bash(npm run lint)",
      "Bash(git status)",
      "Bash(git diff *)",
      "Bash(git log *)",
      "Edit"
    ]
  }
}

Tip: Start conservative and add permissions as you see which prompts you approve repeatedly.

VS Code Extension

  1. Install “Claude Code” from the VS Code marketplace
  2. Open the sidebar panel (Claude icon in activity bar)
  3. Start prompting - inline diffs appear directly in your editor

The VS Code extension provides:

  • Inline diff previews before applying edits
  • Code lens actions on functions and classes
  • File-level suggestions in the explorer
  • Same conversation history as the terminal

Try These First

Once you’re set up, try these prompts to see Claude Code in action:

> Add input validation to the /api/users POST endpoint

> Find all places where we catch errors but don't log them

> Write tests for the auth middleware

> Explain how the payment flow works, step by step

Tips for Effective Use

  1. Be specific - “Fix the login bug” is vague. “The /api/login endpoint returns 500 when the email contains a plus sign” is actionable.

  2. Let Claude read first - don’t paste code into the prompt. Say “read src/auth.ts and explain the token refresh logic.” Claude reads the actual file and stays up to date.

  3. Use multi-turn - start broad (“explain the auth system”), then narrow (“now add rate limiting to the login endpoint”). Claude retains context.

  4. Trust the tools - Claude will read files, search code, and run commands. Let it explore rather than pre-explaining everything.

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