What is llms.txt and does your business need one?

You may have heard that websites should now have an “llms.txt” file. This guide explains what it is, where it goes and how it is laid out. It also gives an honest view on whether your business needs one.

An LLM is a large language model, the kind of AI behind chat assistants. An “agent” is an AI tool that does tasks for a person, such as looking things up.

What is llms.txt?

llms.txt is a proposal published at llmstxt.org. In its own words: “We propose adding a /llms.txt markdown file to websites to provide LLM-friendly content.”

Markdown is a simple way to format plain text. A # sign makes a heading and a dash makes a list item.

The file is meant to be a short guide to your site for AI tools. It “offers brief background information, guidance, and links to detailed markdown files.”

Why was it proposed?

Web pages are built for people to read. AI tools have limited room to take in text, and most whole websites are too big. The proposal says: “Agents are best served by concise, expert-level information gathered in a single, accessible location.”

So the idea is simple. Rather than make an AI tool read your whole site, you give it a short, tidy summary in one place.

Where does the file go?

Usually at the root of your site, so it sits at yourdomain/llms.txt. The proposal says: “The file can be placed at the site root, or at any path within it, covering the pages under that path.”

If more than one file applies to a page, “agents should use the most specific one”. Most small businesses only need one file, at the root.

What goes in it?

The proposal sets out the sections in a fixed order:

• A heading with your business name. This is “the only required section”.
• A short summary in a quote block. A quote block is a line starting with the > sign. The summary holds “key information necessary for understanding the rest of the file”.
• Optional notes in plain text. For example, the areas you cover or your opening hours.
• Optional lists of links under smaller headings. Each item has a link to a page, then a colon and a short note about that page if you want one.
• An “Optional” section, if you need it. By convention this holds “links an agent can skip when a shorter context is needed”.

Because the layout is fixed, it “can be read using standard programmatic-based tools”. In other words, software can read it reliably.

The proposal’s tips for a good file are to keep the wording short, add brief notes to links and avoid jargon. It also suggests a simple test: “Test your file by asking an agent questions about your content, giving it only your llms.txt as a starting point.”

How is it different from robots.txt and a sitemap?

They do different jobs:

• robots.txt tells automated tools what access to your site is acceptable.
• llms.txt is used “on demand, when an agent needs information about a topic while assisting a user.”
• A sitemap lists all your pages for search engines. llms.txt is not a replacement for it: “While sitemaps list all pages for search engines, llms.txt offers a curated overview for LLMs.” Curated means hand-picked.

Keep all three. llms.txt sits alongside the others and replaces neither.

Who proposed it and what is its status?

It is a proposal from its author, published at llmstxt.org. It is not a finished standard. The current version is v2, and “The llms.txt specification is open for community input.”

The proposal reports that many sites now publish an llms.txt file and that documentation platforms generate one automatically. It also says “Chrome’s Lighthouse audits sites for one as part of its agentic browsing checks.” Lighthouse is Google’s free tool for checking websites.

Be clear about where it is used most, though: “llms.txt files are used most heavily for software documentation, where coding agents follow them to find API references and tutorials.” The proposal says the same structure can work for a business setting out what it does and its policies.

Does your business need one?

Here is our honest view.

Reasons to add one:

• It takes little effort. For a small business it is a short text file with your name, a summary and links to your key pages.
• It costs nothing to publish and does not harm your site.
• Writing it makes you set out clearly what you do, where and how to get in touch. That clarity helps on your normal pages too.
• Some website builders already make one for you. llmstxt.org lists Wix as one that “Generates an llms.txt file for every Wix site”. Check whether you already have one before you write your own.

What to be realistic about:

• It is a proposal, not a rule that AI tools must follow. No one can promise that any AI tool will read your file, or that it will change how AI tools describe your business.
• It is mostly used for software documentation, not local businesses.
• It does not fix bigger problems. If your robots.txt blocks AI crawlers, or your text only appears after JavaScript runs, a good llms.txt will not make up for that. (A crawler is the program an AI or search company uses to fetch web pages.)

Our view: if you have half an hour, add one. It is cheap and harmless. But make sure the basics are right first.

How to make one

You can write the file in any plain text editor, following the layout above, and upload it to the root of your site. Keep it short and accurate, and update it when your services or contact details change.

To save time, use our free llms.txt generator. It builds a starting file you can edit.

Check the rest of your site

llms.txt is one small part of being readable by Google and AI tools. Our free check looks at it alongside your robots.txt rules for each AI crawler, HTTPS, whether your text is readable without JavaScript, your sitemap and your structured data. It gives “a score out of 100 and the top three issues for a homepage, in about 10 seconds, with no sign-up.”

If you want the fixes written for you, the full report costs £39, one-off. It includes ready-made fixes, including an llms.txt draft. Monitoring costs £14 a month. It checks your site every month and emails you the result.

Run the free website check