The short answer
No. If you run a local or service business, you don't need an llms.txt generator, and you shouldn't pay anyone to write the file. In our test it made no difference to how often a site appears in Google's AI Overviews.
An llms.txt file is a plain text file at yourdomain.com/llms.txt that lists your key pages for AI tools. It's a community proposal, not a standard, and no search engine or AI company is required to read it. Generators and SEO plugins now make one in a click, which is how a lot of small sites ended up with one they never decided to publish.
The test
We took 397 HVAC, plumbing, electrical and roofing companies from the LVL3 Home Services Growth Index, each ranking for at least 50 searches that show a Google AI Overview. For each one we measured how often the Overview lists its site as a source, using Semrush AI Overview data from October 20, 2026. Then we compared sites with and without llms.txt, holding traffic and trade constant.
The result: sites with the file appeared 0.92 times as often as similar sites without it (95% confidence interval 0.78 to 1.09). That's no difference, and the data rules out a lift bigger than about 9%. It's an association test, not an experiment, and it covers Google AI Overviews only.
Why some people think it worked
Look only at raw medians and the file seems to help. Sites with it score 58 on the Growth Index, against 52 without. But bigger companies are more likely to have the file, and bigger companies score higher anyway. Account for size and the gap disappears. Most "we added llms.txt and it worked" stories skip that step.
Who actually publishes one
Not the web's biggest sites. In The llms.txt Reality Check, we checked the top 1,000 domains on the Tranco list (fetched October 20, 2026). Only 127 of the 620 websites we could reach publish a real file, about one in five. Nearly two-thirds of those come from software, SaaS and developer-tool companies. Of the 72 search engines, portals and social platforms we could reach, zero publish one.
Home services sites are ahead of them: 26% of the 464 companies in the Growth Index had an llms.txt, and about a third of those carried an SEO plugin's signature. That's not a strategy. That's a plugin update.
Your site may say yes when the answer is no
Of those 620 top websites, 136 answer a request for /llms.txt with a web page and a "200 OK" success code, usually their homepage. That's more than the 127 that publish a real file. Any checker that only reads the status code will tell those sites they already have one. Open yourdomain.com/llms.txt in a browser and look.
Google and others say the same
- Google's AI search guide, published May 2026, says sites don't need AI text files to appear in generative search (reported by TechWyse, May 2026).
- A Google analyst said Google doesn't support llms.txt (Search Engine Land, July 24, 2025).
- SE Ranking found no clear link between llms.txt and AI citations across about 300,000 domains (Search Engine Journal, November 20, 2025).
The one case where it earns its keep
If you're a software or documentation-heavy company, write a good one. The file was designed for AI assistants and coding tools that read docs, not for Google's results, and Chrome's Lighthouse added an llms.txt check for AI agents in May 2026. That's why developer-docs companies lead adoption. We didn't test ChatGPT, Claude or Perplexity citations, so we can't speak to those yet.
What to do instead
- Make sure AI crawlers can reach you. In the Growth Index, under 3% of sites block AI crawlers on purpose, but up to 8% have servers that turn them away, often through a firewall or security setting. If the bots can't get in, no file helps.
- Build normal search strength. In the same data, what tracks with AI Overview appearances is overall search strength, not a file. Google's AI answers draw from sites that already rank.
- Check yourdomain.com/llms.txt. If it shows your homepage, your site answers "yes" to every address. Ask your developer to return a real "not found".
- If a plugin already made one, there's no need to remove it. Just don't pay for a better one.
- If someone's selling you one, ask for evidence: a before-and-after against similar sites that didn't add it.
Sources
- The llms.txt Reality Check: top 1,000 domains, Tranco list GQG5K, fetched October 20, 2026; effectiveness test on 397 companies, Semrush AI Overview data, October 20, 2026.
- The LVL3 Home Services Growth Index 2026: 464 operator websites crawled October 20, 2026. AI crawler blocking is an upper bound.
- TechWyse, "Google publishes first official AI search optimization guide, then Chrome starts auditing llms.txt," May 2026.
- Search Engine Land, "Google says normal SEO works for ranking in AI Overviews and llms.txt won't be used," July 24, 2025.
- Search Engine Journal, "llms.txt shows no clear effect on AI citations based on 300K domains," November 20, 2025.