Quick answer
llms.txt is a proposed Markdown file at your site's root that gives AI tools a short summary and a list of key pages. Google has stated its AI features work without any special AI text file. It's optional and cheap to add, but it isn't a ranking or citation lever today.
On September 3, 2024, Jeremy Howard published a short proposal with a simple idea: give AI models a plain-text map of your website, the way robots.txt gives crawlers rules. Two years on, "llms.txt" has its own plugins, generators and a growing list of agencies selling it as an AI visibility fix.
The reality is more modest. Google Search says it doesn't need the file. Google's Chrome team added a check for it to Lighthouse. A large 2026 study found it made no measurable difference to AI citations. This guide sorts out what the file is, what each of those signals means, and whether your site should have one.
What llms.txt is
llms.txt is a plain Markdown file placed at the root of a website, such as yoursite.com/llms.txt, that summarizes the site and links to its most useful pages. The idea is to help large language models find clean, relevant content without wading through menus, ads and scripts.
The proposal on llmstxt.org opens with a single line: "We propose adding a /llms.txt markdown file to websites to provide LLM-friendly content." It was written with documentation sites and developer tools in mind, where a model answering a coding question benefits from a tidy list of reference pages.
It's easy to confuse with two files you may already have:
| File | Purpose | Format | Who reads it |
|---|---|---|---|
| robots.txt | Tells crawlers which parts of a site they may access | Plain text rules | Search engine and AI crawlers |
| sitemap.xml | Lists the URLs you want search engines to find | XML | Search engines |
| llms.txt | Summarizes the site and points to key pages for AI tools | Markdown | Proposed for AI tools; use is limited |
The proposal also suggests offering clean Markdown versions of individual pages, for example a page.md alongside page.html, so an AI tool can read the content without the surrounding layout. Some sites go further and publish an "llms-full.txt" with the full text of their key pages in one file. That variant comes from the community rather than the original proposal.
Why the comparison to robots.txt? Both files live at the same predictable address, both are plain text, and both speak to machines rather than people. The difference is in what they do. robots.txt sets access rules that crawlers follow. llms.txt only offers a suggested reading list, and nothing obliges any tool to read it.
What the file looks like
An llms.txt file has one required part, an H1 heading with the site or project name, plus optional sections: a short summary in a blockquote, and lists of links grouped under H2 headings.
The proposal describes the H1 as "the only required section." After it can come a blockquote with "a short summary of the project," then any number of H2 sections containing Markdown links, each optionally followed by a colon and a short note. A section titled "Optional" is "used, by convention, for secondary information," so tools that need a shorter context can skip it.
Here's an illustrative example for a fictional local plumbing company:
# Riverside Plumbing Co.
> Licensed plumbers serving Riverside and nearby towns since 2009. Emergency repairs, water heaters and drain cleaning.
## Services
- [Emergency plumbing](https://example.com/emergency-plumbing/): 24-hour repairs, call-out areas and response times
- [Water heater installation](https://example.com/water-heaters/): tank and tankless options, typical costs
- [Drain cleaning](https://example.com/drain-cleaning/): what's included and when to call
## About
- [Service areas](https://example.com/service-areas/): towns and ZIP codes we cover
- [Contact and hours](https://example.com/contact/): phone, booking and opening hours
## Optional
- [Blog](https://example.com/blog/): maintenance tips and guidesShort and specific beats long and exhaustive. The notes after each link do the real work. A line such as "tank and tankless options, typical costs" tells a model what it will find on the page without opening it, which is the whole point of the file. Keep the notes factual and plain, without marketing language. The file should point to the pages that best explain what you do, not every URL on the site.
Does Google use llms.txt?
Google Search says you don't need llms.txt to appear in its AI features. Google's Chrome team, meanwhile, added an llms.txt check to its Lighthouse auditing tool. Both statements are true, and they describe different products.
Google Search. Google's AI features documentation, updated December 10, 2025, is direct: "You don't need to create new machine readable files, AI text files, or markup to appear in these features." AI Overviews and AI Mode rely on Google's normal index, so the same pages that rank in search are the ones it can use.
Google's John Mueller went further in a Reddit discussion reported by Search Engine Journal, comparing llms.txt to the old keywords meta tag, a self-description by the site owner that search engines stopped trusting long ago.
Chrome Lighthouse. The Lighthouse llms.txt audit, updated May 5, 2026, belongs to a group of checks for agentic browsing, meaning AI tools that browse sites on a user's behalf. It describes llms.txt as "an emerging convention," notes that providing the file "is optional at the moment," and says a missing file returning a 404 is "marked as Not Applicable (N/A)." Lighthouse only flags a problem when the server returns an error while fetching it.
The plain reading: Google Search doesn't use the file to decide what appears in AI Overviews, and Chrome's tooling acknowledges it as an optional convention for AI agents. Neither treats it as a requirement, and a missing file costs you nothing in either.
For most business owners, that settles the priority question. If your goal is appearing in Google's AI Overviews and AI Mode, the file does nothing Google has said it needs. If you run a site where AI agents may browse on a user's behalf, such as a developer tool or a documentation portal, the Lighthouse check suggests the file may become more useful over time, and adding it now is cheap.
- Google SearchAI text files aren’t needed to appear in AI featuresGoogle Search Central, Dec 2025
- Chrome LighthouseAn optional, emerging convention; a missing file is marked N/AChrome for Developers, May 2026
- SE Ranking study10.13% of nearly 300,000 domains had the file; no effect on AI citationsSE Ranking, Oct 2026
Sources: Google, Chrome for Developers and SE Ranking.
Does it help AI visibility? What the data says
The best public data so far finds no link between having an llms.txt file and being cited by AI systems. That may change if AI companies adopt the file, but for now it isn't a visibility lever.
What the evidence shows:
- Adoption is low: an SE Ranking study by Yulia Deda, published October 15, 2026, examined nearly 300,000 domains and found "just 10.13% had an LLMs.txt file in place."
- No measurable effect: the same study concluded that "LLMs.txt doesn't impact how AI systems see or cite your content today."
- No public commitment: we found no published commitment from a major AI company to read llms.txt when building answers.
- No guarantees: adding the file won't, on its own, get your business mentioned in ChatGPT, Perplexity or Google's AI features.
One study is one snapshot. The SE Ranking data reflects how AI systems behaved when it was collected, and adoption could change that picture if major AI companies start reading the file. Until there's public evidence of that, treat llms.txt as optional housekeeping rather than a strategy.
That doesn't make the file harmful. It means the time you'd spend expecting results from it is better spent on the things AI systems clearly do use, covered further down.
Who should add one: decision table
Add llms.txt if your site is documentation-heavy or serves developers, consider it for large content sites, and treat it as a low priority for local service businesses. The cost is small either way; the real cost is attention taken from work that moves results.
| Type of site | Should you add llms.txt? | Why |
|---|---|---|
| Documentation, SaaS and developer tools | Reasonable to add | The proposal was built for this use, and developer-focused AI tools may read it |
| Content-heavy publishers and blogs | Optional | Can help organize key content, but expect no direct citation effect |
| Ecommerce stores | Optional, low priority | Product feeds, structured data and Merchant Center carry more weight in AI shopping answers |
| Local service businesses | Low priority | Business Profile, reviews, consistent listings and clear service pages come first |
If you run a local business and your site is in good shape, adding the file is a reasonable ten-minute task. If your Business Profile is incomplete or your service pages are thin, do those first.
A quick example of where it does fit: a software company with 400 help articles and an API reference. An llms.txt that lists the getting-started guide, the main API pages and the pricing page gives AI coding assistants a clean entry point. For a dentist with eight service pages, the same file adds little that a well-structured site doesn't already provide.
How to create and check llms.txt in 10 minutes
Creating llms.txt takes about ten minutes: choose your key pages, write a heading and summary, group the links, upload the file to your site's root and check that it loads.
- Pick 10 to 20 key pages. Your homepage, main service or product pages, pricing, about, contact and your most useful guides.
- Write the H1 and summary. The H1 is your business or site name. The blockquote is one or two plain sentences on what you do and where.
- Group links under H2 headings. Use sections such as Services, About and Guides. Add a short note after each link describing what the page covers.
- Add an Optional section for secondary pages, such as the blog index or older resources.
- Save it as llms.txt in plain text with Markdown formatting.
- Upload it to your site's root so it loads at yoursite.com/llms.txt.
- Check it loads by visiting the URL in a browser. You should see plain text, not an error page.
On WordPress, you have two routes. Several SEO and AI plugins can generate and serve the file for you, and some build it from your existing pages. Or you can upload a file you've written through your host's file manager or an FTP client, placing it in the same folder as your robots.txt.
Check it with Lighthouse. Run a Lighthouse report in Chrome's developer tools and look at the agentic browsing checks. If the file loads correctly, the audit won't flag a server error.
Keep it current. When you add, rename or remove key pages, update the file. Links that redirect or return 404 errors make the file less useful.
A few practical details: save the file as plain UTF-8 text, use full URLs including https://, and keep it under a few hundred lines. Add a review of the file to whatever checklist you use when launching or retiring pages, so it never drifts out of date.
What actually earns AI citations
AI citations come from crawlable pages with clear answers, backed by consistent business information and trust signals from other sites. These are the levers with evidence behind them, and they help in regular search too.
- Crawlable pages: search engines and AI crawlers need access. Check robots.txt allows Googlebot and the search crawlers AI tools use, such as OpenAI's OAI-SearchBot.
- Clear, answer-first content: a direct answer under each heading, written in plain language, is easy for AI tools to find and quote.
- Structured data that matches the page: LocalBusiness, Product or Article markup describing what's visible to readers.
- Reviews and mentions: reviews on several platforms and mentions on trusted local or industry sites.
- Consistent business details: the same name, address, phone and hours everywhere your business appears.
- Fresh, dated content: visible "last updated" dates and current facts on the pages that answer common questions.
None of these depend on llms.txt, and every one of them also helps your regular search rankings, which is why they belong ahead of it on any to-do list.
Our guides to GEO vs SEO, what generative engine optimization is, how to get cited in AI Overviews and how to rank in ChatGPT cover each of these in depth. For crawler and indexing checks, see our technical SEO audit checklist. Our GEO services put the whole set into practice.
Common llms.txt mistakes
The most common llms.txt mistakes come from treating it as more important than it is, or from setting it up in a way that contradicts your other files.
Avoid these:
- Blocking AI crawlers in robots.txt while adding llms.txt: a map to your content does little if the crawlers that would use it are turned away.
- Listing every URL: the file works best as a short guide to key pages. A full sitemap belongs in sitemap.xml.
- Treating it as a fix for weak content: the file points to pages; it can't make thin pages more useful.
- Linking to pages that redirect or 404: check every link when you create the file, and again whenever pages change.
llms.txt FAQs
What is an llms.txt file?
llms.txt is a proposed Markdown file placed at a website's root that summarizes the site and links to its key pages for AI tools. It was proposed by Jeremy Howard on llmstxt.org in September 2024. Its only required part is an H1 heading with the site's name.
Does Google use llms.txt?
Google Search has said AI text files aren't needed for its AI features, and AI Overviews and AI Mode rely on Google's normal index. Chrome's Lighthouse tool includes an optional llms.txt check for AI agents, and a missing file is marked not applicable.
Is llms.txt mandatory?
No. It's an optional, proposed convention. Google says no special AI files are required for its AI features, and Lighthouse marks a missing file as not applicable. A 2026 SE Ranking study found it didn't affect how AI systems cite content.
How do I create an llms.txt file?
Write a Markdown file with your site name as an H1, a one- or two-sentence summary in a blockquote, and links to 10 to 20 key pages grouped under H2 headings. Save it as llms.txt, upload it to your site's root and check it loads in a browser.
What's the difference between llms.txt and robots.txt?
robots.txt tells crawlers which parts of your site they may access, and search engines and AI crawlers follow it. llms.txt is a proposed summary and list of key pages for AI tools. robots.txt controls access; llms.txt only suggests useful content.
Sources
- llmstxt.org, "The /llms.txt file," Jeremy Howard, September 3, 2024: https://llmstxt.org/
- Google Search Central, "AI features and your website," updated December 10, 2025: https://developers.google.com/search/docs/appearance/ai-features
- Chrome for Developers, Lighthouse llms.txt audit, updated May 5, 2026: https://developer.chrome.com/docs/lighthouse/agentic-browsing/llms-txt
- SE Ranking, llms.txt study, Yulia Deda, October 15, 2026: https://seranking.com/blog/llms-txt/
- Search Engine Journal, "Google's llms.txt guidance depends on which product you ask," May 20, 2026: https://www.searchenginejournal.com/googles-llms-txt-guidance-depends-on-which-product-you-ask/