An llms.txt is a plain-text file you place at the root of your site. It lives at yourdomain.com/llms.txt and holds a clean summary of who you are, what you offer, and where your important information sits. The point is to hand an AI model a tidy map of your site instead of letting it guess from scattered bits of HTML.
It’s written in Markdown and there’s no magic to it: a heading with your business name, one line describing you, then sections of links to your key pages with a short note on each. You can write it in an afternoon.
The part nobody leads with: Google doesn’t use it
I’ll be blunt, because there’s a lot of hype around this. Google has said plainly that you don’t need an llms.txt to appear in AI Overviews or its AI Mode. Its normal crawler already reads your site. If your only goal is showing up in Google, llms.txt does nothing for you today. Full stop.
So what’s it for? Everything that isn’t Google. Tools and assistants that work over your content, like ChatGPT when it browses, Perplexity, or AI code editors such as Cursor and Claude Code, can read an llms.txt when it exists and use it to find your information without the noise.
Why it’s still worth doing now
Three concrete reasons, no promises:
- It’s cheap. An afternoon of work, and near-zero maintenance if your site doesn’t change weekly.
- Almost nobody has one. That’s an edge while it lasts. The day it becomes standard, it stops being a differentiator.
- It forces you to get organized. Writing the file makes you decide which 5 to 10 pages actually matter. That exercise alone sharpens how your whole site reads.
What goes in it
Pick the pages that define your business, not all of them. A realistic set for a services business:
- Home: what you do and for whom, in one line.
- A page for each core service.
- About, or who’s behind it.
- Contact.
- Pricing, or “how we charge,” if it’s public.
Each link gets a short, honest description. No filler, no keyword stuffing. It doesn’t help, and in normal content Google treats it as spam.
The mistake of thinking it replaces the real work
The llms.txt is a map, not the territory. It doesn’t replace clear content, a robots.txt that doesn’t block AI bots, structured data, or mentions off your own domain. It’s one small piece of a bigger puzzle. If someone sells it to you as “the” fix for showing up in AI, be skeptical.
What you can check right now
This site (blackindex.co) has a real llms.txt. You can open it at blackindex.co/llms.txt and see exactly the structure I’m describing. It’s not a theory: it’s what we run on our own site before recommending it to anyone.
Want us to check whether your site is set up for AI systems to read it cleanly? The llms.txt, the robots.txt, and your structured data all get reviewed in the same pass.