Calling a language model from a web page no longer requires an API key, a per-token invoice, or sending user data to a server. Chrome's Prompt API, powered by Gemini Nano, is stable in extensions since Chrome 138 and on the web since Chrome 148: a page in Chrome can ask the browser to summarize, classify or rewrite, locally. For extension developers, this is a category shift: AI becomes a browser capability, on par with storage or notifications. It is not magic, though. The model downloads on...