Think of it like a briefing document you hand to AI before it represents your brand. A short text file that lives at yoursite.com/llms.txt and tells AI systems — ChatGPT, Perplexity, Claude, and others — exactly what your company does, which pages matter, and how you want to be described.
Like handing a journalist your press kit before an interview — except the journalist is AI, and the interview is every question a prospect ever asks about your category.