What is Claude Code? Anthropic's CLI for Agentic Development

The Terminal Gets a Brain

Claude Code is a CLI tool, not a web app. You install it, run it from your terminal, and it drives a Claude session that can read your files, run shell commands, use git, and interact with your IDE. It is the difference between asking an AI a question and working with an AI on your actual codebase.

The key distinction: Claude Code operates on your local environment. It sees your project structure, your git history, your configuration files. It is not running in a sandboxed demo — it is working with the same files you are.

What You Can Ask It

Claude Code can handle the full development lifecycle:

• Read and understand your existing codebase
• Write new features, tests, and refactors
• Run your build tools and test suites
• Create and review git commits
• Navigate unfamiliar codebases and explain architecture
• Debug issues by reading logs and tracing execution

It does this through a tool-use interface — it can call tools that interact with your system, and you can see exactly what it is doing before it does it.

How Sessions Work

A session starts with claude in your terminal. You give it a task. It works through it, showing you its plan, asking for confirmation on risky operations, and updating you on progress. You can interrupt it mid-task, ask it to try a different approach, or take over manually and hand it back.

Sessions persist context. Claude Code remembers what you have worked on within a session, what has been tried and failed, and what the goal is. Between sessions it can resume previous work if you want to continue where you left off.

Who It Is For

Developers who want an AI that works on their actual codebase, not a hypothetical one. It is particularly useful for large refactors, test writing, understanding unfamiliar code, and the kind of tedious work that eats your afternoon but does not require deep architectural decisions.