AI Visibility
llms.txt, Explained in Plain English
By the LA Web Design team5 min read
You may know robots.txt, the little file that tells search crawlers where they're allowed to go. llms.txt is its AI-era counterpart: a plain text file that hands language models a clean summary of what your site is about and where the important pages live — so when an assistant reads up on your business, it gets the story you wrote instead of the one it pieced together.
What it is, concretely
llms.txt is a plain markdown file at the root of your website (yoursite.com/llms.txt). It contains a short description of who you are, followed by organized links to your key pages with one-line summaries. Some sites add a companion, llms-full.txt, carrying the complete site content in one machine-readable page — so an AI system can understand everything you offer without crawling dozens of pages.
Why it exists
AI assistants work under tight constraints: limited context, limited time per answer. When someone asks ChatGPT or Claude for a recommendation, the systems favor sources they can read quickly and trust. A clean llms.txt is the difference between an AI parsing your homepage's navigation soup and being handed an organized briefing about your business.
Does it actually matter yet?
Honest answer: it's early. llms.txt is a young convention, and no AI company guarantees they'll read it. But the cost is nearly zero, the downside is nonexistent, and the direction of travel is unmistakable — a growing share of buying decisions start as questions to an assistant instead of searches. The sites that are machine-readable early tend to become the sources those systems keep citing. It's the cheapest bet in marketing.
What it doesn't replace
llms.txt complements the fundamentals, it doesn't replace them: structured data (schema markup) on every page, semantic HTML, real answers written in plain language, and a robots policy that doesn't accidentally block AI crawlers. If those basics are missing, start there — llms.txt is the garnish, not the meal.
How to add one
For a small site, you can write one by hand in any text editor and upload it to your site root. The better version is generated: our builds create llms.txt and llms-full.txt automatically from the site's actual content, so they update themselves whenever the site changes and can never drift out of date. However you do it, the test is simple — visit yoursite.com/llms.txt and read it as if you were an assistant meeting your business for the first time. Would you know who to recommend?