What an Artifact actually is
An Artifact is what you get when you ask Claude for something buildable and it hands back a running thing instead of a code block you have to copy, paste, and wire up yourself. The chat generates a small, self-contained web page (HTML, CSS, and JavaScript, or a React component) and renders it live in a panel next to the conversation. You type, it runs. You ask for a change, it rebuilds in place.
That's the whole shift. The output stops being instructions for a tool and becomes the tool.
Under the hood, each Artifact runs inside a sandboxed iframe. That sandbox is the source of both its powers and its limits, so keep it in mind.
Where they actually earn their keep
