llms.txt is being sold as the sitemap for AI. Google's own guide says it does not use the file. Here is what is confirmed, what is not, and what has no evidence behind it at all.
A plain text file you put at the root of your domain. Jeremy Howard proposed it in September 2024 as a way to hand AI systems a short, curated guide to your most important pages. It is a proposal, and the page itself says so: "A proposal that those interested in providing LLM-friendly content add a /llms.txt file to their site."
That word matters. The file is not a standard, and no major AI company has committed to reading it.
Google published an official guide for optimising a site for its generative AI features. It addresses llms.txt directly, twice, and both times to say the file is unnecessary.
"LLMS.txt files and other 'special' markup: You don't need to create new machine readable files, AI text files, markup, or Markdown to appear in Google Search (including its generative AI capabilities), as Google Search itself doesn't use them." Google Search Central, AI optimisation guide
"For Google Search, you can ignore tactics like 'chunking' content, creating unnecessary AI text files (like llms.txt), or pursuing inauthentic mentions." The same guide, in its closing recap of what to focus on
The guide also notes that Google may crawl and index many kinds of files, and that discovering a file is not the same as treating it specially. Finding your llms.txt is not evidence that it was used.
| Claim | Status |
|---|---|
| "Google said it is helpful for AI discoverability and indexing efficiency." | Not said. Those two phrases appear nowhere in Google's guide. The guide says the opposite. |
| "Google promoted llms.txt, then walked it back a week later." | No evidence. The guide is a single document with one consistent position: use SEO fundamentals, and AI text files are not a lever. |
| "Sites with llms.txt appear more often in ChatGPT and AI Overviews." | Unsupported. No published study shows this. Claims like it come from vendors selling the service, and none name their method. |
| "It is like robots.txt, but for AI." | The analogy fails. robots.txt works because crawlers agreed to obey it, and Google documents that it does. No major AI company documents llms.txt as a citation signal or a visibility requirement. |
A rule only works when the other side has agreed to it. robots.txt has
twenty-five years of crawler compliance behind it. llms.txt has an author, a proposal page,
and a growing number of plugins that will generate the file. Generating a file is not the
same as anyone reading it.
The file is easy to add. Yoast SEO has generated one since version 25.3, and the setting is a single toggle. If you want the file, it costs you a minute.
Content quality still decides outcomes. Google's guide is blunt that unique, first-hand content matters more than any of its other suggestions, and that good SEO practice continues to apply to its AI features.
An AI-facing file layer may well standardise. robots.txt took years to become universal. Something will probably fill this role. That is a reason to keep watching, not a reason to build now and sell it.
We had an llms.txt on our own site, and we listed it as one of the things we build for clients. We removed both. The file does not do anything we can prove, and a claim we cannot measure does not belong in a report about measurement.
That is the whole test we apply here. Not whether a tactic is popular, and not whether a competitor is selling it. Whether the effect is measurable, and whether we can show it to you.
If you want an llms.txt file, add one. It is free and it is quick. Do not expect it to change how often AI engines name you, and treat anyone who promises that it will as someone who has not shown their working.
What decides whether an engine names your business is whether your pages answer the questions buyers actually ask, in a form an engine can quote. That has not changed.