llms.txt: The File AI Reads First (Part 1 of 3)
Last updated 2026-06-16
A tiny markdown file at /llms.txt tells AI tools what your site is about. Here is what it is, why it matters now, and what goes in it.
- llms.txt
- GEO
- AI search
- AI crawlers
A new front door
For thirty years we wrote robots.txt for search engine crawlers. A quiet little file that told Google where to go and where to stay out.
Now there is a new visitor. The model. ChatGPT, Claude, Gemini, Perplexity. It does not browse the way Google does. It reads, summarizes, and answers in one breath.
llms.txt is the front door you build for that visitor. A plain markdown file at the root of your site, at /llms.txt. A title, a one line summary, and a short list of the pages that matter. That is the whole idea.
Why a tiny text file matters
A model has a small attention span. Not because it is lazy, because context windows are finite. Your homepage is a wall of navigation, banners, cookie notices, and scripts. To a model that is noise wrapped around a sentence of signal.
So the model guesses. It skims, it compresses, and it decides what your company does based on whatever it could grab fastest.
llms.txt takes the guessing away. You write the summary. You choose the links. You hand the model the clean version of your story instead of hoping it reverse engineers one from your markup.
What actually goes in it
The spec is refreshingly small. In order:
- One H1 with your name. This is the only required part.
- A blockquote summary. One line that says what you are and who you serve.
- Optional plain sentences with context a model should know.
- Sections of links, each written as a real markdown link with a short note.
That is it. Human readable, model readable, and easy to keep honest.
It is not magic. It is hospitality.
llms.txt does not bribe the model. It does not buy you a ranking. It sets the table for a guest who reads fast and decides quickly.
You already do this for people. You write a clear nav, a tight homepage, an about page. llms.txt is the same courtesy, aimed at the software that more and more of your buyers now ask before they ask you.
The brands that win the next few years will be the ones who treat the model like an important visitor. Not an intruder. A guest.
Start here
Open your-domain.com/llms.txt right now. Most likely you get a 404. That is normal, and that is the opportunity.