Quick answer
llms.txt does not work as a search ranking or citation signal as far as anyone can show. Google says it has no effect on Search, including AI features, and no major AI search company has confirmed using it. Some agents and developer tools read it, so it can help documentation sites, but it is optional.
Few SEO topics have generated as much noise relative to evidence as llms.txt. It was proposed in 2024, adopted quickly by documentation platforms, and sold by some agencies as the key to AI visibility. Here is what is actually known.
What the search companies have said
Google has been the most explicit. Gary Illyes said at Search Central Live in July 2025 that Google doesn't support llms.txt and isn't planning to. John Mueller has compared it to the old keywords meta tag. On 15 June 2026, Google updated its guide to optimising for generative AI features to say that llms.txt has no effect, positive or negative, on Search, including AI Overviews and AI Mode.
OpenAI, Anthropic and Perplexity have not announced that their search products use llms.txt to decide what to cite. Their crawler documentation covers robots.txt rules, not llms.txt.
Anthropic and others publish llms.txt files for their own documentation, which is sometimes cited as evidence that AI companies "use" it. It shows they find it useful for documentation readers, including coding assistants, not that it affects search or citations.
Does llms.txt work? What server logs show
Site owners who have published the file and watched their logs report a consistent pattern: requests for /llms.txt come mostly from SEO tools, checkers and curious developers, with occasional fetches from AI agents and coding assistants. Major AI search crawlers are rarely seen requesting it. That matches what the companies have, and haven't, said.
You can check your own: after publishing the file, filter your server or CDN logs for requests to /llms.txt and group them by user agent. A month of data tells you more about your site than any blog post.
Where llms.txt can help
| Use | Does it help? | Why |
|---|---|---|
| Google rankings or AI Overviews | No | Google says it has no effect |
| Citations in ChatGPT, Claude or Perplexity search | Unproven | No company has said it is used |
| Coding assistants reading your API docs | Sometimes | Tools that look for it can load a clean summary |
| Agents navigating a large catalogue or help centre | Possibly | A short map of key pages saves crawling |
| Signalling that you think about AI | Not really | Visitors never see it |
Should you publish one?
Publish one if it costs you almost nothing: your documentation platform generates it, or you can generate it from your sitemap at build time. Documentation, developer tools and large help centres benefit most.
Skip it, for now, if the time would come out of work with a known effect, such as allowing AI search crawlers, putting content in server-rendered HTML, or rewriting pages to answer questions directly. Those changes affect whether you can be found and cited; llms.txt doesn't, on current evidence.
If you publish one, keep it valid and current. The format and a working example are in the llms.txt checker guide, and the wider picture of what does affect AI visibility is in the AI search readiness checker guide. Seotific reports whether a site has the file but gives it zero weight in the score, in line with the evidence.
What to do instead
If your goal is to appear in AI answers, the changes with documented effects are: allow the AI search crawlers (OAI-SearchBot, Claude-SearchBot, PerplexityBot) in robots.txt and your firewall; put content in server-rendered HTML; open each page with a direct answer; and earn mentions on sites those products already cite. Each is covered in the AI search guides linked above.
Frequently asked questions
Does Google use llms.txt?
No. Google has said it doesn't support llms.txt, and its June 2026 guidance on generative AI features states that the file has no effect on Search, including AI Overviews and AI Mode. Normal SEO practices are what count for Google's AI features.
Does ChatGPT read llms.txt?
OpenAI hasn't said that ChatGPT search uses llms.txt to choose or cite sources. ChatGPT search relies on OAI-SearchBot crawling and third-party search providers. A user can ask ChatGPT to read the file directly, but that isn't the same as it affecting citations.
Is llms.txt a waste of time?
For most small business sites and blogs, it's a low priority rather than a waste. It takes minutes to create and does no harm. For documentation and developer tools it has more value. Don't let it replace work on crawler access and content.
Can llms.txt hurt my SEO?
No. Google says it has no positive or negative effect on Search. The only risk is maintenance: a stale file pointing to deleted pages misleads any agent that reads it, so generate it automatically if you publish one.
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