Claude CodeLesson 1 of 25

Claude Code Overview

Claude Code is a command-line tool that gives Claude direct access to your project files and your terminal. Instead of copying code back and forth, Claude reads, writes, and runs things in your actual codebase.

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What is Claude Code?

Claude Code is an agentic coding tool made by Anthropic. You install it once and run it from the terminal inside any project folder. Claude then has full visibility of your files and can take action on them directly.

Unlike Claude Chat — where you paste code in and paste answers back — Claude Code is wired directly into your project. It reads your existing code, understands the context, makes the change, and saves the file. You review the diff and move on.

See it in action

You open your terminal, navigate to any project, and run claude. Then describe what you want in plain English.

Terminal
# Navigate to your project
$ cd my-website
$ claude
Claude Code ready. What would you like me to do?
> Add a dark mode toggle to the header. Save the changes.
Reading header.tsx...
Reading globals.css...
Adding dark mode toggle component...
Adding CSS variables for dark theme...
Done. 2 files updated: header.tsx, globals.css

No copy-pasting. No switching tabs. Claude edits the actual files on your machine.

In short: Claude Code is to your codebase what Claude Chat is to a text box — except it can actually open, edit, and save files, run commands, and remember your whole project.

Claude Chat vs Claude Code

Both use the same Claude model. The difference is what Claude can doduring the conversation.

💬 Claude Chat💻 Claude Code
Access your filesNo — you paste code manuallyYes — reads all files in your project
Save changesNo — you copy the output yourselfYes — writes and saves files directly
Run commandsNoYes — can run npm, pytest, git, etc.
Where you use itBrowser (claude.ai)Terminal, VS Code, or Desktop App
Setup neededNone — just open browserInstall once via npm
Best forWriting, Q&A, quick explanationsReal coding tasks in a real project
Rule of thumb: If the task involves files on your computer, use Claude Code. If it is a question or a writing task, Claude Chat is fine.

Key Capabilities

Claude Code covers the full development workflow — not just writing new code.

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Read & write any file

Opens, modifies, and saves files across your whole project automatically.

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Understand context

Reads your entire codebase before acting — no need to paste anything.

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Find & fix bugs

Describe the symptom. Claude traces it through multiple files and fixes it.

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Write & run tests

Generates test files, runs the suite, and iterates until tests pass.

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Run terminal commands

Executes npm scripts, git commands, build tools — anything you could type.

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Autonomous multi-step tasks

Complete a whole feature end-to-end: files, tests, docs, commit.

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Connect external tools

Use MCP to pull in APIs, databases, and third-party services.

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Works in teams

Integrates with GitHub Actions, Slack, and CI/CD pipelines.

What You Will Learn

This section has 26 lessons covering everything from first install to advanced automation. Here is the shape of the journey.

Getting set up

Installation, how it works, permission modes, the Desktop App, VS Code integration

Doing real work

Getting better results, debugging, building apps, writing tests

Power features

CLAUDE.md, memory management, sub-agents, skills, MCP, hooks

Configuration & tools

Explore .claude directory, settings, connecting tools, Chrome extension

Integrations

Code review, Git, GitHub Actions, Slack, and best practices

Who Is Claude Code For?

  • 👨‍💻Developers who want to spend less time on repetitive coding tasks and more time on design and problem-solving.
  • 👩‍🎓Students and beginners who want to build real projects but sometimes get stuck — Claude Code explains as it works.
  • 🏃Solo builders and indie hackers who need to move fast without a full team.
  • 🏭Teams that want to automate code reviews, testing, and CI/CD without custom tooling.

What's Next

Overview done. Next: installing the Claude Code CLI and running your first session — takes less than a minute.