What Is Claude Code? A Complete Guide to Anthropic's AI Coding Assistant | Code Boost
Description: Claude Code is an AI-powered agentic coding tool built by Anthropic that lives directly in your terminal. Unlike traditional code assistants that autocomplete lines or answer questions in a chat windo

Article

# What Is Claude Code? A Complete Guide to Anthropic's AI Coding Assistant

By Matt · Feb 24, 2026

Claude Code is an AI-powered agentic coding tool built by Anthropic that lives directly in your terminal. Unlike traditional code assistants that autocomplete lines or answer questions in a chat window, Claude Code understands your entire codebase, executes commands, edits files across your project, manages git workflows, and handles complex development tasks through natural language conversation.

Whether you are a seasoned developer looking to speed up repetitive tasks or someone exploring AI-assisted development for the first time, Claude Code represents a fundamentally different approach to writing software. Instead of switching between a chatbot and your editor, you stay in your terminal and describe what you need done in plain English.

## Claude Code at a Glance

Feature | Details
--- | ---
Made by | Anthropic
Interface | Terminal CLI, VS Code, JetBrains, Cursor, Windsurf, browser (claude.ai/code)
Pricing | Claude Pro ($20/mo), Max 5x ($100/mo), Max 20x ($200/mo)
Models | Claude Sonnet (default), Claude Opus (Max plans)
Platforms | macOS, Linux, Windows (native + WSL)
Open Source | Yes — github.com/anthropics/claude-code
Key capability | Full agentic coding: reads files, writes changes, runs tests, commits to git

## What Is the Claude Code CLI?

At its core, Claude Code is a command-line interface that gives you conversational access to Anthropic's most capable AI models. You launch it from your terminal, navigate to your project folder, and start describing what you want to accomplish. Claude Code then reads your files, understands the context, and takes action by editing code, running tests, creating new files, or executing shell commands on your behalf.

When people say "Claude Code CLI," they mean the core terminal interface. After installation, you type `claude` to launch an interactive session. From there, you type natural language requests, use slash commands like `/init` to generate a project configuration file or `/clear` to reset context, and reference specific files using the @ symbol.

The CLI supports several flags for different workflows. Running `claude -p` followed by a prompt gives you a single response without entering interactive mode, perfect for scripting and automation. The `claude -c` flag resumes your last conversation, and `claude --model` lets you switch between AI models. There is no separate CLI package to download — the main installation gives you everything.

## Who Makes Claude Code?

Claude Code is developed and maintained by Anthropic, the AI safety company founded in 2021 by former OpenAI researchers including Dario and Daniela Amodei. Anthropic builds the Claude family of large language models that power the tool, and focuses on creating reliable, interpretable AI systems. Claude Code is one of their flagship developer products alongside the Claude API and Claude.ai chat interface.

The tool is open source on GitHub at github.com/anthropics/claude-code, meaning you can inspect the code, report issues, and follow development progress. Anthropic actively maintains it with new releases shipping regularly through automatic background updates.

## Claude Code Is Not Limited to the Terminal

Claude Code integrates with popular editors like VS Code, Cursor, Windsurf, and JetBrains IDEs through native extensions. You can even run it directly in your browser at claude.ai/code without any local setup, or hand off sessions between devices using the teleport feature. For a detailed walkthrough of editor integration, see our guide on how to use Claude Code in VS Code and Cursor.

## What Makes Claude Code Different From Other AI Coding Tools?

Most AI coding assistants work as plugins inside your editor, offering suggestions as you type. Claude Code takes a different philosophy by following the Unix tradition of composable tools. You can pipe logs into it, run it inside CI/CD pipelines, chain it with other command-line utilities, or spawn multiple agents working on different parts of a task simultaneously.

Claude Code also has full agentic capabilities. It does not just suggest code and wait for you to copy and paste. It reads files, writes changes, executes terminal commands, runs your test suite, commits to git, and even opens pull requests. You review and approve each action, keeping you in control while Claude handles the heavy lifting.

The tool connects to external services through the Model Context Protocol (MCP), which lets it read design docs from Google Drive, update tickets in Jira, pull data from Slack, or interact with any custom tooling you build. To understand how all of this works under the hood, read our deep dive on how Claude Code works, what models it uses, and how to extend it with MCP.

## What Can You Do With Claude Code?

On the routine side, Claude Code excels at:

- Writing tests for untested code
- Fixing lint errors across a project
- Resolving merge conflicts
- Updating dependencies
- Generating release notes and changelogs
- Explaining unfamiliar codebases to onboard faster

For more complex work, Claude Code implements entire features spanning multiple files, refactors large codebases, debugs tricky issues by reading error logs and tracing through code paths, and supports multi-agent workflows where a lead agent coordinates several sub-agents working on different components simultaneously.

## How Good Is Claude Code?

Claude Code's quality depends on which model you use and how well you structure your requests. With Opus, the most powerful model, it handles complex architectural reasoning, multi-file refactoring, and subtle debugging with strong results. It consistently ranks among the top AI coding tools for understanding large codebases and maintaining context across extended development sessions.

For routine tasks like writing tests, implementing features from clear specifications, fixing bugs, and managing git workflows, Claude Code is highly effective with any model tier. The CLAUDE.md configuration file helps provide Claude Code with explicit context about your project's specifics — coding standards, preferred libraries, architecture decisions — reducing the need to re-explain context in every session.

## How Much Does Claude Code Cost?

Claude Code is included with Anthropic subscription tiers. The Pro plan at $20 per month gives you access with moderate usage limits. Max plans at $100 and $200 per month offer significantly higher usage caps and access to Opus. You can also use pay-as-you-go API billing through the Anthropic Console. For a full breakdown of every plan, usage limits, and cost optimization tips, check out our detailed Claude Code pricing guide.

## Getting Started With Claude Code

Setting up Claude Code takes just a few minutes on macOS, Linux, or Windows. Anthropic provides native installers that do not require Node.js. After installing, you authenticate with your Anthropic account and navigate to your project directory to start your first session.

Follow our step-by-step installation guide covering Mac, Windows, and Linux. Once installed, our guide on setting up, configuring, and keeping Claude Code updated walks you through authentication, CLAUDE.md files, and your first productive session. When you are ready to dive in, see our complete practical guide to using Claude Code.

## Frequently Asked Questions

### Is Claude Code free to use?

Claude Code is not free — it requires an Anthropic subscription. The Pro plan at $20/month includes Claude Code with moderate usage limits suitable for learning and occasional development work. The free Claude.ai plan has very limited Claude Code functionality. For daily professional use, the Max 5x plan at $100/month is the most practical option.

### What programming languages does Claude Code support?

Claude Code works with any programming language. It has strong support for the most common languages — JavaScript, TypeScript, Python, Go, Rust, Java, Ruby, PHP, C/C++, and more — because these are well-represented in its training data. It handles less common languages too, though suggestions may be less precise for niche or proprietary languages.

### Does Claude Code require internet access?

Yes. Claude Code requires an active internet connection to communicate with Anthropic's API servers. The tool itself runs locally, but all AI processing happens in the cloud. This means your code is sent to Anthropic's servers for processing — a consideration for sensitive or proprietary projects.

### How is Claude Code different from Claude.ai?

Claude.ai is a web-based chat interface for general conversation. Claude Code is a specialized developer tool with terminal access, file system read/write permissions, shell command execution, and full agentic capabilities. Claude Code is designed specifically for coding workflows, while Claude.ai is a general-purpose assistant. Both use the same underlying Claude models.

### Can Claude Code work with any codebase size?

Claude Code can handle most real-world codebases effectively. Its context window can hold substantial amounts of code, and the CLAUDE.md configuration file helps it focus on the most relevant parts of large projects. For very large monorepos with millions of lines of code, it works best when given specific directories or files to focus on rather than attempting to load everything at once.

### Is Claude Code better than GitHub Copilot?

They solve different problems. GitHub Copilot is optimized for inline autocomplete and suggestions as you type — fast, lightweight, and deeply integrated into your IDE. Claude Code is a full agentic system that can implement complete features, debug across files, manage git, and run your tests. Many developers use both: Copilot for line-by-line coding speed, Claude Code for larger tasks and autonomous workflows.