Claude Code is a terminal-based agent: install it, point it at a repository, and describe what you want done in plain English. It reads the relevant files, makes edits across as many of them as the task requires, runs commands like tests or builds, and explains what it changed — all without leaving the shell.
The terminal-first design is deliberate. It fits directly into existing developer habits — the same window as git, your test runner, and your build tool — instead of asking you to switch to a browser tab and copy code back and forth by hand.
It's genuinely useful for tasks that span multiple files: renaming a widely-used function, updating a pattern across a dozen call sites, or tracing why a test fails through several layers of the codebase. Reading and cross-referencing that much code manually is exactly the kind of repetitive work agents handle well.
Permissions are worth understanding before you start. Claude Code can be configured to ask before running commands or editing files, which is the safer default for anything touching a shared branch or production configuration — you want a chance to say no before it acts, not just a summary after.
It works best paired with normal engineering discipline: a clean git status before you start, small focused asks instead of open-ended ones, and a real review of the diff before it merges. Treat it as a fast collaborator that still needs a second pair of eyes, not a replacement for one.