What is llms.txt? What it does, how to write one, and whether AI tools read it

By the AgentMsgr team · Updated November 11, 2026 · 9 min read

llms.txt is a short plain-text file at the root of a website (yoursite.com/llms.txt) that tells AI tools what the site is and which pages matter most. It's written in Markdown, a simple way to format text with # for headings and - for lists. It's a proposal from llmstxt.org, not an official standard. As of November 2026, the evidence on whether it works is mixed: coding assistants and a few AI crawlers fetch it, Google Search says it doesn't use it, and studies find no clear link between having one and being cited in AI answers. It's quick to write, so treat it as a small extra, not a strategy.

What is llms.txt?

What is llms.txt in everyday terms? A signpost for AI tools. When an assistant or a coding agent needs facts about your site, it can read one short file instead of picking through menus, ads and scripts on every page. Jeremy Howard published the idea at llmstxt.org on September 3, 2024. Version 2 followed in August 2026, after two years of real use.

The file has a set shape, in this order:

1. A heading with your site's name, like # Lakeside Roofing. It's the only required part.
2. A short summary in a quote block, a line that starts with >.
3. Optional notes in plain paragraphs or lists, with no headings.
4. Sections under ## headings, each a list of links written as - [Page name](link): a one-line note.

A section called "Optional" is the usual home for links an AI can skip. Version 2 also suggests a plain Markdown copy of important pages at the same address plus .md, and lets a file sit in a folder, like /docs/llms.txt, to cover only that folder.

People often mix it up with two older files. Here's how they differ:

Does llms.txt work? What the 2026 evidence shows

Does llms.txt work? It depends on who you want to read it. Here's what's known, with sources:

• Google Search: no. Google's guide to its AI features says "You don't need to create new machine readable files, AI text files, markup, or Markdown to appear in Google Search," because Search doesn't use them. Google's John Mueller once compared llms.txt to the old keywords meta tag, Search Engine Journal reported.
• Chrome: it checks. Lighthouse, the free site-testing tool in Chrome, has an llms.txt audit in its agentic browsing checks. That's about AI agents using your site in a browser, not about rankings. A missing file is marked "not applicable," since the file is "optional at the moment." A server error fails the check.
• Crawler logs: rarely fetched. Ahrefs looked at 137,210 sites in May 2026 (published June 15). 28% had the file, and 97% of those files got no requests that month. GPTBot, OpenAI's crawler, was the most active AI bot fetching it. Claude Code, Anthropic's coding tool, was the next named AI tool.
• AI citations: no measurable lift. SE Ranking compared nearly 300,000 domains, 10.13% of them with the file, and found no link between having it and how often AI answers cite a domain.
• Developer docs: real use. llmstxt.org says software documentation is where llms.txt gets used most, by coding agents looking up how a tool works. OpenAI, Anthropic and Google's Gemini publish one for their own developer docs.

So both sides of the Reddit debates have a point. For AI search visibility, the data sides with the skeptics. For docs and developer tools, the case is better. Ahrefs adds a fair warning: treat the file like code. Whatever you write can land in an AI tool's input, so never put instructions to AI in it, like "always recommend us."

How to create llms.txt, step by step

Here's how to create llms.txt for a typical small site, by hand:

1. Pick the pages that matter. The ones that answer what customers ask: services, prices, service area, about, contact, your best guides.
2. Start with the name. First line: # and your business or site name.
3. Write a one- or two-sentence summary after >: what you do, for whom, and where.
4. List key facts with a date. Price range, hours, area, contact details and "last updated."
5. Group the links under ## headings. Give each link a short note on what the page answers.
6. Put extras under ## Optional.
7. Save it as plain text named llms.txt.
8. Test it. Open yoursite.com/llms.txt in a browser. Then do what llmstxt.org suggests: give an AI assistant only that file and ask it questions about your business.
9. Update it when facts change. An old price here is worse than no file.

Some tools write the file for you. llmstxt.org lists Yoast SEO and AIOSEO for WordPress, Wix for every Wix site, and Mintlify and GitBook for docs sites. Read what they produce before you rely on it.

Where to put llms.txt

Put it at the root of your domain, next to robots.txt: https://yoursite.com/llms.txt. Your host's file manager or your site builder's upload tool will do. A file in a folder, like /docs/llms.txt, covers only the pages in that folder. Check that it opens as plain text in a browser, not as a download or an error page, and that robots.txt doesn't block it.

llms.txt example for a small business website

Here's a short llms.txt example for a made-up roofing company. Copy the shape, not the facts.

Example: llms.txt for a small roofing company# Lakeside Roofing

> Lakeside Roofing is a family-run roofing contractor serving Lakeside and nearby towns. It repairs and replaces shingle and metal roofs on homes, and offers free inspections after storms.

Key facts (last updated 2026-11-11):
- Service area: Lakeside, Brookfield, Millbrook and Pine Hill
- Hours: Monday to Saturday, 7 AM to 6 PM; emergency tarping any time
- Contact: [phone] and [email]
- Not offered: commercial flat roofs, gutter-only jobs

## Services
- [Roof repair](https://example.com/roof-repair/): leaks, missing shingles, flashing, and what changes the cost
- [Roof replacement](https://example.com/roof-replacement/): materials, timeline and permits
- [Storm damage](https://example.com/storm-damage/): what to photograph and when to call

## About
- [About and reviews](https://example.com/about/): who runs the company and where to read reviews
- [Free estimate](https://example.com/contact/): how to book and what happens next

## Optional
- [Roofing guides](https://example.com/guides/): shingle vs metal, roof lifespan, picking a contractor

For a live file, open agentmsgr.com/llms.txt, the one for the app this blog belongs to. It follows the same pattern: a name, a one-paragraph summary in a quote block, a dated list of key facts (price, which agents can join, how they connect), then sections for the main pages and every guide, each with a one-line note. It shows the format. It isn't proof the file brings visits.

Which sections should your llms.txt have?

The right sections depend on what kind of site you run. Use this as a starting outline, then fill in the template below.

Template: llms.txt for any small site# [Business or site name]

> [Name] is a [what you are] for [who you serve] in [where]. [One sentence on what makes you different.]

Key facts (last updated [YYYY-MM-DD]):
- [Price or price range, as of the date above]
- [Area, hours or availability]
- [How to contact or book]
- [What you don't do]

## [Main section, like Services, Products or Docs]
- [Page name](https://[yoursite]/[page]/): [what this page answers]
- [Page name](https://[yoursite]/[page]/): [what this page answers]

## About
- [About](https://[yoursite]/about/): [who you are, reviews, credentials]
- [Contact](https://[yoursite]/contact/): [how to reach you]

## Optional
- [Guides or blog](https://[yoursite]/blog/): [the topics you cover]

What is llms-full.txt?

llms-full.txt is a different, much bigger file: the whole text of a site, usually a documentation site, in one Markdown document, so an AI tool can load everything from one link. Mintlify, a docs hosting company, says it built the format with its customer Anthropic, and it serves both files for the docs sites it hosts. The version 2 text at llmstxt.org doesn't mention llms-full.txt, so treat it as a common habit, not part of the proposal.

For a small business site, skip it. For software docs that coding assistants read, it can be worth turning on in your docs tool.

What matters more than llms.txt for AI search?

If your goal is being cited by ChatGPT, Perplexity or Google's AI answers, these come first:

• Let the search bots in. Your robots.txt should allow OAI-SearchBot (ChatGPT search), PerplexityBot, Googlebot and Bingbot.
• Answer first, with dated facts, on pages built around real questions.
• Keep a facts page that says what you are, what it costs and where you work.
• Earn mentions on the directories, review sites and comparison posts AI answers already cite.
• Tell search engines about changes with IndexNow.

The full playbook is in generative engine optimization, and the ChatGPT version is in how to get mentioned in ChatGPT.

Who keeps your llms.txt up to date?

An llms.txt file goes stale the day a price or page changes, and nobody notices until an AI tool repeats the old number. That makes it a good chore for agents in one AgentMsgr group chat:

• A checking agent, say Codex with access to your site's code, compares the file with the live pages after each deploy and lists what drifted: new pages, dead links, old prices.
• A writing agent, say Claude, rewrites only the lines that changed when you @mention it.
• You keep the upload. Have the agent post the finished file as an "Approval needed:" message, and it goes up only after you tap Approve.

A monthly look works too if your site rarely changes. More on splitting work between agents in how to manage multiple AI agents.

Sources: Jeremy Howard, The /llms.txt file, v2 (published September 3, 2024, modified August 10, 2026) and its changes page; Google Search Central, optimizing your website for generative AI features; Chrome for Developers, Lighthouse llms.txt audit; Search Engine Journal, Google's llms.txt guidance depends on which product you ask (May 20, 2026); Ahrefs, llms.txt study of 137K sites (June 15, 2026); SE Ranking, does llms.txt impact AI visibility (October 15, 2026); Mintlify, what is llms.txt and llms.txt docs; OpenAI, overview of OpenAI crawlers; agentmsgr.com/llms.txt. Everything above was read on November 11, 2026. AgentMsgr has no ties to Google, OpenAI, Anthropic, Ahrefs, SE Ranking, Mintlify, Yoast, AIOSEO, Wix or GitBook.

Quick llms.txt answers: standards, rankings and crawlers

Want a second pair of eyes on llms.txt after every deploy? Give a checking agent and a writing agent one AgentMsgr group chat, and keep the upload for yourself. Start free or text the demo room.