What Is Claude Code?

Claude Code is Anthropic's official AI coding agent that runs directly in your terminal. Unlike chat-based AI tools, Claude Code operates inside your development environment — reading files, running commands, editing code, and managing your project end-to-end through natural language.

How Claude Code Works

Claude Code is a command-line interface (CLI) that gives Claude direct access to your local filesystem, shell, and development tools. You interact with it through a persistent terminal session — type a request, and Claude reads the relevant files, makes changes, runs tests, and reports back.

Because it runs in your terminal rather than a browser, Claude Code can take real actions: editing multiple files at once, running your test suite, executing shell commands, and working with your actual project structure. There is no copy-pasting between a chat window and your editor.

Claude Code is built on Claude — Anthropic's large language model — and uses the same underlying intelligence. The difference is the interface: instead of a chat UI, you get a programmable agent that is deeply integrated into your workflow.

Key Capabilities

Codebase-Aware Editing

Claude Code reads your entire project before responding, so it understands your existing architecture, naming conventions, and dependencies. Edits fit naturally into what you have already built.

Terminal & Shell Integration

Run shell commands, execute tests, install packages, and manage processes — all without leaving the Claude Code session. Claude can read command output and iterate based on results.

Multi-File Refactoring

Rename a function across 50 files, extract a shared utility, or restructure a module — Claude Code handles changes that span your entire codebase in a single operation.

Git Integration

Create commits, write commit messages, manage branches, and review diffs. Claude Code understands your Git history and can use it to inform decisions about how to make changes safely.

Extensibility

Extend Claude Code with skills, plugins, MCP servers, and agents. Claude Bazaar lists 3865+ community-built extensions that add specialized capabilities for every stack and workflow.

Claude Code vs. Other AI Coding Tools

Several AI coding tools exist, but Claude Code occupies a distinct position: it is a terminal-first agent rather than an IDE plugin or chat interface.

Feature Claude Code IDE AI plugins Chat interfaces
Reads your full codebase Yes Partial Manual paste
Runs shell commands Yes Limited No
Multi-file edits Yes Varies No
Extensible via community tools Yes — 3865+ extensions Some No
Works in any editor Yes — terminal-based Editor-specific Yes

Getting Started with Claude Code

Claude Code is available as an npm package. Install it globally with Node.js 18 or higher:

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

Once installed, run claude from any project directory to start a session. Claude Code will index your codebase and wait for instructions.

An Anthropic account and API key are required. Usage is billed based on tokens consumed per session.

Extending Claude Code

Claude Code's real power comes from its extension ecosystem. The community has built 3865+ tools across four types:

Popular Extensions to Try First

Top MCP Servers

See all top MCP servers →

Frequently Asked Questions

Is Claude Code free?

Claude Code is free to install but requires an Anthropic API key. Usage is billed per token, so you pay based on how much you use it. Anthropic offers a free tier with limited credits for new accounts.

Does Claude Code work with any editor?

Yes. Because Claude Code runs in the terminal, it is editor-agnostic. It works alongside VS Code, Neovim, JetBrains IDEs, or any editor you prefer. There are also official IDE extensions that embed Claude Code directly into VS Code and JetBrains.

How is Claude Code different from GitHub Copilot?

GitHub Copilot is primarily an inline autocomplete tool integrated into your IDE. Claude Code is a full coding agent that understands your whole project, runs commands, makes multi-file edits, and can work autonomously on larger tasks. The two tools complement each other — many developers use both.

Can Claude Code access the internet?

By default, Claude Code operates on your local filesystem. MCP servers can extend this — for example, a GitHub MCP server lets Claude read and write to remote repositories, or a web search MCP server lets it fetch live documentation. You control which external connections are enabled.

Is it safe to give Claude Code access to my codebase?

Claude Code shows you every action before executing it by default, so you can review file edits and shell commands before they run. You can also use permission modes to restrict what Claude is allowed to do without prompting. Sensitive files and directories can be excluded via .claudeignore.

Explore More