Prototype
A quick version built to help you decide something, such as which layout or how an interaction should feel. It is meant to be thrown away, and the real one gets built properly afterwards.
Agents make these so cheap that you can see three before choosing. That speed sharpens the old danger, because a prototype looks finished. Vibe coding one is fine. Keeping it, and adding real users, is the mistake.
Say it to your agent
“Build three layouts for the settings page in a scratch folder, plain HTML, behind one switcher so I can flip between them. No tests, no framework. This is throwaway: I pick one, and then we build it properly in src/.”