More AI products now build screens on the fly: a chat answer becomes a form, a table, a booking flow. Nobody reviewed that screen, and it's different every time. RUI tests these generated interfaces both proactive and reactive (evals): it lists every button and form, what each says it does, what it actually does, and where to fix it. Also in the lab: Agentable UI, an open-source agent-native library for people and AI agents. A person sees a table to sort; their agent sees a tool it can call.