Answers "does this survive?" for one component. Renders it on a page in every state real use can put it in, and hands that page over as a visual report of what broke.
Answers "how was this built?" about an interface. Give it a URL and name the thing you're curious about, and it reads the layers that produce the effect. Reads the whole frontend instead when you don't name a thing. From a screenshot it reconstructs rather than reads and says so.
Interface review of a change rather than a screen: uncommitted work, the current branch, or a pull request. Covers interface quality, not correctness, tests, or security.
Answers "which of these?" rather than "is this right?". Builds several genuinely different versions of one piece of UI behind a picker in the real page, so you can flip between them and promote the one that wins.
Claude Code skill that draws 39 kinds of editorial diagrams as self-contained HTML and SVG
Field guide and agent skill for spotting and fixing the generic look of AI-generated interfaces