No. An llms.txt file is optional: its effect on AI answers is not proven, and Google Search does not use it. In Citevio's October 2026 crawl, 17,470 of 66,161 readable US dental websites had one (26.4%), and nearly half of those files (47.4%) name the SEO plugin or website platform that generated them.
Many of these files were produced by a tool, not written by hand. Of the 17,470 files, 8,277 (47.4%) name the tool that generated them: Wix, Yoast SEO, Rank Math, All in One SEO or, in 57 cases, another named generator. Another 942 (5.4%) name no generator but start with the same kind of "# www." heading. Wix's help centre says Wix automatically generates and maintains your llms.txt file
, and Yoast's specification says the file will be updated weekly by a scheduled action
. A dental website can therefore have one because a setting was switched on in a platform or plugin, not because anyone wrote it.
Source: Citevio crawl of US dental websites, October 2026; every file was re-read and classified from the raw crawl files on 28 October 2026. Wix Help Center and Yoast developer documentation opened 28 October 2026.
How many dental websites have an llms.txt file?
About one in four: 17,470 of the 66,161 US dental websites where Citevio's October 2026 crawl could check the file, or 26.4%. The raw count was higher. 19,142 sites answered a request for /llms.txt, but 1,672 of those answers were not llms.txt files: 1,194 sites returned a copy of their robots.txt file, 476 returned an empty file and 2 returned an error page. Of the real files, the table shows how many name the tool that made them.
| What the file contained | Sites | Share of the 17,470 files |
|---|---|---|
| Names Wix (website platform) | 3,190 | 18.3% |
| Names Yoast SEO (WordPress plugin) | 2,401 | 13.7% |
| Names Rank Math (WordPress plugin) | 1,502 | 8.6% |
| Names All in One SEO (WordPress plugin) | 1,127 | 6.5% |
| Names another generator | 57 | 0.3% |
| Subtotal: names its generator | 8,277 | 47.4% |
| No generator name found in the opening text; starts with a "# www." heading | 942 | 5.4% |
| No generator name found in the opening text; other layouts | 8,251 | 47.2% |
A file that names no generator was not necessarily written by a person. In a hand-read random sample of 30 files, several unsigned files also followed fixed template layouts. Read 47.4% as the share whose text names the tool that made it; the true share of tool-made files is likely higher, but this crawl does not measure it.
Does Google use llms.txt for AI Overviews or AI Mode?
No. Google's guide to generative AI features in Search says 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
. The same guide adds that keeping such a file will neither harm nor help your site's visibility or rankings in Google Search, as Google Search ignores them
. Google added this note to the guide on 15 June 2026, according to its documentation change log. For a dental practice, that means the file plays no part in whether the practice appears in AI Overviews or AI Mode.
Source: Google Search Central, AI optimization guide (last updated 10 July 2026) and its documentation updates page, opened 28 October 2026.
Do ChatGPT, Perplexity or Claude read llms.txt?
None of the three companies' crawler documentation says that its crawler reads a website's llms.txt file. OpenAI's crawler page explains site controls through robots.txt: OpenAI uses OAI-SearchBot and GPTBot robots.txt tags to enable webmasters to manage how their sites and content work with AI
. Perplexity's crawler page likewise says we recommend allowing PerplexityBot in your site’s robots.txt file
. Both pages mention llms.txt only as an index of the company's own developer documentation. Anthropic's help article on its crawler does not mention the file at all. Published research points the same way: SE Ranking's study of almost 300,000 domains, as reported by SE Visible, found no measurable link between having an llms.txt file and getting cited more often by AI systems
.
Sources: OpenAI, Overview of OpenAI Crawlers · Perplexity Crawlers · Anthropic crawler help article · SE Visible, 7 September 2026. All opened 28 October 2026.
What is an llms.txt file actually for?
It is a proposed file that gives AI tools a short, plain-text map of a website. Jeremy Howard published the proposal on 3 September 2024 and describes it as A proposal to standardise on using an /llms.txt file to provide information to help agents use a website
. It is not an adopted web standard. The current version, dated 10 August 2026, notes that The AI labs themselves publish llms.txt files for their own developer docs
and that Chrome’s Lighthouse audits sites for one as part of its agentic browsing checks
. Its main use so far is software documentation that coding tools read. A dental website is a different case: patients and search engines read its ordinary pages.
Source: llmstxt.org, "The /llms.txt file, v2", opened 28 October 2026.
How can you check whether your dental website already has an llms.txt file?
Open your website address followed by /llms.txt in a browser, for example yourpractice.com/llms.txt; the site root is the usual place for the file. If a plain-text page appears, read it. If it names Wix, Yoast SEO, Rank Math or All in One SEO, that tool created it. Wix and Yoast keep their files updated automatically. Yoast's specification says Yoast SEO includes the 5 latest updated posts/pages/custom post types in the llms.txt file
, gives cornerstone content priority, and lets you choose pages by hand with Manual page selection. On Wix, Once you edit the file, it will stop updating automatically so your changes are preserved.
If the address shows your robots.txt rules or a blank page instead, there is no real llms.txt file at the root.
Sources: Yoast developer portal, llms.txt functional specification · Wix Help Center, Understanding your site's llms.txt file. Opened 28 October 2026.
Should you pay an agency to create an llms.txt file?
We found no published study showing that the file brings AI citations, and SE Ranking's study found no link, so it is hard to justify as a paid line item on its own. Yoast, Rank Math, All in One SEO and Wix already generate the file for many sites, and Google Search ignores it. If your site has one, keep it accurate; Google says maintaining one for other services or systems that use these files
is fine. What AI search engines do need is access to your pages and facts they can read as text. Our guide to testing whether AI can read your dental website shows how to check that, and the dental website checklist for AI search lists the items Google documents.
One quick check you can run now is what AI engines currently say about your practice.
Prefer to question the engines by hand? See how to check what ChatGPT says about your practice.
How we measured this
The figures come from Citevio's October 2026 crawl of US dental websites: 66,410 sites returned readable HTML, and the llms.txt check could be made on 66,161 of them. A site counted when a request for /llms.txt returned a file. We then read every returned file and sorted it by its text: a copy of robots.txt, empty, an error page, a file that names its generator in its first 3,000 characters, an unsigned file starting with a "# www." heading, or neither. Counts were re-run from the raw crawl files on 28 October 2026. The crawl covers websites listed as dental businesses; in a hand-read sample of 30, 3 sites were not dental practices (a marketing firm, a dental lab and an eye clinic), so the figures describe US dental websites, not practices. State-level figures are not given because the misread answers were not measured state by state. Our method for AI answers is described in how we measure AI visibility.
We wrote this page for dental practice owners who have been offered an llms.txt file, or found one on their own website, so the decision rests on what Google and the AI companies have published and on what 17,470 dental websites' files actually contain.
Common questions
What is an llms.txt file?
An llms.txt file is a plain-text file, usually at a website's root such as yourpractice.com/llms.txt, that lists a site's main pages for AI tools. It was proposed by Jeremy Howard in September 2024 and is not an adopted web standard.
Does Google use llms.txt for AI Overviews?
No. Google's AI optimization guide says Google Search does not use llms.txt or similar AI text files, and that keeping one neither harms nor helps a site's visibility or rankings in Google Search, including AI Overviews and AI Mode.
Does ChatGPT read llms.txt files?
OpenAI does not say so. Its crawler documentation, opened 28 October 2026, describes site controls through robots.txt tags for OAI-SearchBot and GPTBot and mentions llms.txt only as an index of OpenAI's own documentation.
How many dental websites have an llms.txt file?
In Citevio's October 2026 crawl, 17,470 of 66,161 readable US dental websites had one, or 26.4%. 47.4% of those files name the SEO plugin or website platform that generated them.
Why does my dental website have an llms.txt file I never made?
Your website platform or SEO plugin probably created it. Wix generates and maintains the file automatically, and Yoast SEO, Rank Math and All in One SEO can generate one. Open yourpractice.com/llms.txt and look for the tool's name in the text.
Can an llms.txt file hurt my rankings in Google?
Not according to Google. Its AI optimization guide says maintaining one will neither harm nor help a site's visibility or rankings in Google Search, because Google Search ignores these files.