Most vibe-coded builds sink before the first prompt, because nobody said what "done" looks like. Answer five questions. Get a brief you paste into any coding agent.
Paste this as the first message to your coding agent. It carries the finish line, the must-do list, the angle, the box, and the proof.
Your brief goes to a coding agent (Llama 3.3 70B on Cloudflare Workers AI). It returns one HTML file, built to the brief and nothing more. Then you do your proof walk on it, because the agent saying "done" is a claim, not a fact. The preview runs in a locked sandbox, so saving and reloading only work in the downloaded file: download it, open it, walk it there.