llms.txt, explained in plain English

What is llms.txt?

llms.txt is a markdown file that sits at the root of your website, at /llms.txt, and summarises your site for AI assistants: who you are, what you offer, and which pages matter most. It was proposed in September 2024 by Jeremy Howard, co-founder of Answer.AI, as a simple convention any site can adopt.

The problem it solves is practical. An AI tool reading your website has to wade through menus, scripts and cookie banners to find the substance, and it can only take in so much text at once. llms.txt hands it the substance directly, as a curated brief in a format language models handle well.

llms.txt vs robots.txt: description vs permission

The two files are often confused because they live in the same place. They do opposite jobs.

• robots.txt is permission. It tells crawlers which URLs they may fetch, and says nothing about what your site means. Controlling which AI bots may read you at all is AI crawler management, a separate decision.
• llms.txt is description. It assumes the reader is welcome and tells it what your business is, in your own words, with pointers to your best pages.
• sitemap.xml sits in between. It lists every URL but attaches no meaning to any of them. llms.txt is deliberately selective and deliberately descriptive.

The exact format

The proposal is strict enough to be machine-readable and loose enough to write by hand:

• An H1 heading with your business or site name. This is the only required element.
• A blockquote immediately after it: a short summary of what you do and who you serve.
• Optionally, a few plain paragraphs of key facts.
• H2 sections containing markdown link lists in the form - [page title](url): one-line description.
• An optional section headed ## Optional for secondary links a tool can skip when it is short of room.

Here is a complete example for a fictional UK plumbing firm. Swap in your own names, links and facts and you have a working file:

# Hartley Plumbing and Heating

> Family-run, Gas Safe registered plumbing and heating company
> covering Preston and central Lancashire since 1998. Boiler
> installation, servicing, emergency repairs and bathrooms.

We install and service gas boilers, fix leaks and plumbing
faults, and fit bathrooms. Two-van team, all engineers Gas Safe
registered. Emergency call-outs answered 7 days a week.

## Services
- [Boiler installation](https://example-plumber.co.uk/boiler-installation/): new gas boilers supplied and fitted, with manufacturer warranties
- [Boiler servicing](https://example-plumber.co.uk/boiler-servicing/): annual servicing and gas safety certificates for homes and landlords
- [Emergency plumber](https://example-plumber.co.uk/emergency-plumber/): same-day response for leaks, bursts and boiler breakdowns

## About
- [About us](https://example-plumber.co.uk/about/): the team, qualifications and areas covered
- [Reviews](https://example-plumber.co.uk/reviews/): customer reviews and case studies
- [Contact](https://example-plumber.co.uk/contact/): phone, email and call-out hours

## Optional
- [Heating advice blog](https://example-plumber.co.uk/blog/): guides on boiler care and energy efficiency

How to create yours, step by step

• 1. Pick your pages. List the ten to twenty pages that genuinely explain your business: services, about, contact, proof. Leave out tag archives and thin pages.
• 2. Write the summary. One blockquote covering what you do, where, and for whom. Write it the way you would brief a new employee, not the way you would write an advert.
• 3. Write the file. Any text editor works. Follow the structure above, keep every description to one factual line, and save it as llms.txt.
• 4. Upload it to your web root so it loads at yourdomain.co.uk/llms.txt as plain text, next to robots.txt.
• 5. Test it and keep it current. Open the URL in a browser, run our free SEO checker, which detects whether a site serves an llms.txt file, and revisit the file whenever your services or coverage change.

Does llms.txt actually work today?

Honest answer: adoption is early. No major search or AI company has formally committed to reading llms.txt, and Google has not connected it to Search or AI Overviews. On the other side of the ledger, some AI tools and documentation platforms already generate or consume it, plenty of sites publish one, and it costs nothing and takes about an hour.

That makes it an early-mover position rather than a guarantee: it cannot hurt you, it may already help with some tools, and if the convention becomes standard you are ahead of everyone who waited. We publish one ourselves and create them within our AI Search Visibility Package, alongside signals with firmer evidence behind them, like structured data. To see where your wider search health stands first, a full SEO audit covers both the classic and the AI side.

llms-full.txt: the bigger sibling

The same proposal defines llms-full.txt: one large markdown file containing the full text of your key pages, so a tool can ingest your whole site in a single fetch. Documentation sites use it heavily. For a typical business website it is optional; start with llms.txt and add the full variant only if you have deep reference content worth shipping whole.