Stacks·10 min read·May 3, 2026

What Is Claude Code? The AI Coding Agent in Your Terminal

Claude Code reads your files, runs commands, edits code, and commits changes. All from your terminal. What it does, what it costs, and how to start using it.

Claude Code is Anthropic's AI coding agent. It runs in your terminal, reads your project files, writes and edits code, runs shell commands, and commits to git. Not a chatbot with a code block. An agent that operates directly on your codebase.

You install it with one command, type claude in any project directory, and start talking to it. It sees your file tree, understands your code, and makes changes in place. No copy-pasting between a browser and your editor.

The Problem Nobody Talks About

Most AI coding tools put a wall between the AI and your actual project. You paste code into a chat window. The AI responds with a code block. You copy it back into your editor. You lose context every time you switch tabs. The AI doesn't know what the rest of your codebase looks like, so it makes assumptions that break things.

IDE integrations (Copilot, Cursor) get closer by sitting inside your editor. But they're still limited to the files you have open. They can't run your tests, check your git history, or execute a build to see if their changes actually work.

Claude Code skips all of that. It runs in your terminal with full access to your project. It reads any file, runs any command, and edits code directly. When it makes a change, it can run your tests to verify it didn't break anything. When it's done, it can commit the result. The whole loop happens in one place.

Why It's Different

It runs commands. Not just code suggestions. Claude Code can run your test suite, start your dev server, check build output, grep your codebase, and use git. If you can do it in a terminal, Claude Code can do it too.

It sees your whole project. Not just the file you have open. It reads your directory structure, finds relevant files on its own, and understands how things connect. Ask it to fix a bug and it will trace the issue across files without you pointing to each one.

It edits in place. No code blocks to copy. Claude Code writes directly to your files. You see the diff and approve or reject it.

MCP connections. Connect it to Notion, Postgres, GitHub, Slack. It reads and writes to external tools as part of your conversation.

CLAUDE.md for persistent context. Drop a markdown file at the root of your repo and Claude Code reads it on every session start. Your conventions, your file structure, your rules.

What It Costs

Claude Code comes bundled with Claude Pro ($20/month) or Claude Max ($100/month or $200/month). Pro gives you solid usage for individual work. Max removes most rate limits for heavy daily use.

There's also an API option if you want to pay per token instead of a flat subscription. No free tier for Claude Code specifically.

Step 1: Install

You need Node.js 18+ on your machine. Then:

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

Run claude in your terminal. First launch prompts you to authenticate with your Anthropic account. Takes about 30 seconds.

Step 2: Use It on a Real Project

Navigate to any project directory and run claude. It indexes your project and you start talking.

Some things to try on your first session:

Explore: "Read this project and tell me what each folder does." Good first move on any repo you're not familiar with.

Fix: "Here's the error I'm getting: [paste error]. Find the cause and fix it." Claude Code reads the relevant files, traces the issue, and applies the fix.

Build: "Add a /health endpoint that returns the app version and uptime." It finds where your routes live and writes the endpoint.

This is a preview. The full guide continues inside.

The complete version includes everything above plus:

Plus 12 other full guides on agent builds, MCP setups, and Claude workflows. All free inside.

  • Step 3: Set up CLAUDE.md (persistent project context)
  • Step 4: The commands you'll use every session (/compact, /clear, /cost)
  • Skills and slash commands (community extensions)
  • What Claude Code is NOT (common misconceptions)
  • Honest limitations (context window, rate limits, confident mistakes)
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