How this works, and what it costs. The knowledge base is a file of sourced passages shipped with the page. Your question is scored against every passage with cosine similarity in a loop in your browser — no vector database, no server, no API call, no key, and nothing about your question leaves this page. Cost to run: nothing.

A language model can be added later to phrase the answers more naturally, with the same hard rule: it may only state a number that appears in the retrieved passages. The handler shipped with this site does exactly that when you add a free API key.