I locked my AI's design output with JSON. It worked perfectly — and everything looked like a spreadsheet

Mass-produce web tools with an AI agent and you will hit this wall: the design drifts on every generation. Same instructions, subtly different colors, spacing, and component shapes each time. Running 600+ tools in five locales, I went through three distinct eras of trying to lock the design down. Each era had a failure worth writing down. Era 1: define the UI in JSON → it locked. And then First attempt: define each tool's UI as JSON and generate the page from it. Scope: simple calculator-type…