Claude Code

Overview Claude Code is Anthropic's CLI coding agent — a persistent AI engineer that lives in your terminal, reads your files, edits them, runs your commands, and reports back. Launched in early 2025 and iterated aggressively through the year, it is the tool that pushed the "autonomous agent that actually finishes multi hour tasks" bet from research demo to shippable product. By 2026 it is the second half of the modern solo dev stack for a large and growing cohort of engineers. The one line positioning: Claude Code is not a copilot — it is a junior engineer who never sleeps and never opens Slack. There is no editor. There is your existing editor, plus a CLI agent running alongside it that behaves like a full participant in the codebase rather than a suggestion engine. You describe a task — "migrate this project from Pages Router to App Router, keep all API contracts stable, run the tests after each file, and update the docs" — and Claude Code will grind through it decision by decision, for an hour if that's what it takes. It reads code with judgment, not just token proximity. It writes plans, checks its plans, and pushes back when the plan is bad. When it hits an error, it typically debugs itself and continues. When it can't decide, it asks. Under the hood, Claude Code runs on the same Sonnet 4.5 and Opus 4.7 models that power claude.ai, plus the specialized Haiku model for lower cost background…