llms.txt is a plain-text file at the root of a domain that tells large language models what a site is about, which pages matter, and how to describe it accurately. It plays the same role for AI engines that robots.txt and sitemap.xml play for classic crawlers.
ChatGPT, Perplexity, Claude and Google AI Overviews summarise sites from whatever they can parse. A concise, structured llms.txt reduces hallucinated descriptions and increases the odds of being cited with correct product names, prices and categories.
MagicGEO serves the file from a dedicated endpoint and logs which AI crawlers fetch it, so you can see GPTBot, ClaudeBot, PerplexityBot and OAI-SearchBot visits over time. The file is regenerated whenever your catalog changes.