Vibe Coding?Your Agent explained its design and choices.Is it reflected in the Interface?
Generative UI tools narrate their own design decisions: a three-column grid, accessible contrast, keyboard-navigable tabs. We built a benchmark to check whether those decisions are reflected in the interfaces they generate.
We call the gap Design Theater: plausible, confident design reasoning that bears little relationship to the artifact it describes.
- 0.75
- Mean thinking fidelity. Roughly one in four stated design rationales never appears in the interface.
- 34%
- Failure rate on functional UI tasks.
- 0.54
- Mean adherence to UX principles in the prompt.
- Claude
- Bolt
- ChatGPT
- Vercel v0
- Firebase
Start here
01
What user-facing design reasoning is
When you ask a code agent to generate an interface, it usually explains itself along the way: what it will build, which design principles it is following, which tradeoffs it is making. That explanation is written in the language of an expert designer. Yet nothing checks it against what gets built.
02
Why the gap matters
Design Theater is a performance of design expertise. A fluent rationale invites less scrutiny of the interface it describes, so the people now reviewing generated interfaces (product managers, engineers, first-time creators or non-designers) may trust an interface because its explanation sounds deliberate.
03
What the benchmark adds
Two metrics make two failure modes auditable: design rationales that were never implemented, and UX principles the prompt implied but the tool missed. A third metric studies design homogenization: how similar the interfaces are when different tools get the same prompt.