Claude Code for Beginners: Everything You Need to Know (2026)

Claude Code is Anthropic's terminal-based AI coding agent. This tutorial takes you from installation through to advanced usage with SKILL.md skills and MCP servers.

Quick Answer: Claude Code is Anthropic's terminal-based AI coding agent. It requires Node.js 18+ and an Anthropic API key, installed globally via npm. Key features include code generation, review, refactoring, testing, skill customization, and integration with external tools via MCP servers.

Part 1: Installation and Setup

Claude Code requires Node.js 18+ and an Anthropic API key.

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

Set your API key:

export ANTHROPIC_API_KEY=your-key-here

Add the export to your .bashrc or .zshrc to make it persistent. Navigate to a project directory and start:

cd your-project
claude

Try something simple first: "What does this project do? Summarize the architecture."

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Browse all Claude Code skills

Part 2: Core Workflows

Code generation: Describe what you want. "Add a user authentication module using JWT tokens. Include login, logout, and token refresh endpoints."

Code review: "Review the changes in the last commit. Focus on security issues and performance."

Refactoring: "Refactor the database module to use the repository pattern. Update all callers."

Testing: "Write unit tests for the authentication module. Cover the happy path and edge cases."

Part 3: Skills

Skills are SKILL.md files that customize how Claude Code behaves.

Where Skills Live

• Global skills: ~/.claude/skills/ (apply to all projects)
• Project skills: .claude/skills/ in your project root (apply to one project)

Installing Skills

Browse and download skills from Agensi, then place them in your skills directory. Claude Code loads them automatically.

Essential Skill Categories

Frontend design skills change how Claude Code generates UI components. Code review skills standardize what Claude Code checks during reviews. Testing skills define your testing conventions.

Part 4: MCP Servers

MCP servers connect Claude Code to external tools. Edit ~/.claude/config.json:

{
  "mcpServers": {
    "github": {
      "command": "npx",
      "args": ["@github/mcp-server"],
      "env": { "GITHUB_TOKEN": "your-token" }
    }
  }
}

Most useful MCP servers: GitHub (PRs and issues), Supabase (database access), Playwright (browser testing), Context7 (framework docs), Figma (design files).

Part 5: Advanced Tips

Reduce token usage: Use Sonnet for most tasks, Opus only for complex reasoning. Write specific prompts. Install skills (less trial-and-error).

Combine multiple skills: A common stack: frontend design skill + testing skill + documentation skill + git skill.

Next Steps

1. Install Claude Code and run it on a project
2. Browse skills on Agensi and install one that matches your stack
3. Set up one MCP server (GitHub is a good starting point)