llms.txt is a proposed plain-text file, published at a site's root (/llms.txt), that gives an AI model a Markdown index of a site's content — a # Site name heading, a short description, and a list of pages with titles and optional summaries. Adoption by AI vendors is partial and unconfirmed; Google's own guidance is that sites don't need special files for AI Search. It's a low-cost, forward-looking addition, not a guarantee of anything.
What it isn't
It isn't enforced like robots.txt — nothing requires a crawler to read or respect it. It also isn't a ranking or citation mechanism on its own; the load-bearing work for AI visibility is crawler access, server-rendered content, and structured data.
On Shopify, WordPress, and Next.js
Not generated automatically by Shopify today. A small number of WordPress SEO plugins have started adding support. On Next.js, npm install ai-visibility and generate it with LLMSTextGenerator from ai-visibility/generators.
Related
llms.txt vs. robots.txt · Docs: generating llms.txt from a content directory · GEO