Auto-Generating JSON-LD: Page Signals, Type Heuristics, and a Careful Gemini Prompt

The naive version of this tool is one prompt: "Here is a URL, write the JSON-LD for it." We tried that mental model early and threw it out. An LLM handed a bare URL will produce schema that looks perfect and is quietly wrong. It guesses an author when the page has none. It invents a publication date. On a commerce page it will cheerfully write a price that appears nowhere in the markup. The output validates, parses, and ships, and then an AI engine reads a fabricated author name as a confirmed f...