Do you need an llms.txt file?
It is one of the most-recommended AEO tactics going around. It is also one of the least evidenced. Here is the straight answer.
No, you do not need an llms.txt file, at least not as a ranking or citation factor. Independent studies have found no measurable benefit to being cited by AI, and Google has said directly that you do not need to create special AI files like it. Treat it as an optional, low-cost experiment at most, and put your effort into real content and technical fixes instead.
What it is
An llms.txt file is a proposed text file you place at the root of your site, meant to describe your content and structure for large language models, loosely modelled on the long-standing robots.txt. The idea is reasonable on its face: give the machines a clean map. The trouble is the evidence that it does anything.
What the evidence says
Independent analyses of which signals correlate with AI citations have found no measurable effect from llms.txt. In at least one study, removing it from the model actually improved the model's accuracy, and only a small minority of sites had the file at all, including almost none of the most-cited domains. Crawler logs from the AI bots show the file being requested very rarely. None of that proves it can never help, but it does mean there is currently no good reason to believe it moves citations.
Google has been blunter still. It has stated that you do not need to create AI text files like llms.txt, and senior Google staff have compared it to the old keywords meta tag, which is to say a signal nobody uses any more.
Plenty of AEO advice will tell you to add an llms.txt today. We would rather tell you the truth and save you the time, because a tool you cannot trust on the small calls is not a tool you should trust on the big ones.
What to do instead
Spend the time you would have spent on llms.txt on the things that actually correlate with being cited: answering questions directly near the top of the page, making sure your content is readable without JavaScript, clear structure and valid schema, real authorship, and authentic mentions across the web. Those are covered in how to get cited by AI answer engines.
Should you add one anyway?
If you have spare time and it costs you nothing, there is little harm in it, and there is a reasonable argument that machine-readable site descriptions may matter more as agentic tools mature. Just keep it in proportion: it is a tidy experiment, not a lever. Do not let a missing llms.txt worry you, and be wary of any audit that marks you down for not having one.
Frequently asked questions
What is an llms.txt file?
An llms.txt file is a proposed text file placed at the root of a site, intended to describe the site's content and structure for large language models, loosely modelled on robots.txt. It is a community proposal, not an official standard.
Does Google use llms.txt?
No. Google has stated that you do not need to create special AI files like llms.txt, and has compared it to the old keywords meta tag. Google does not use it as a ranking or citation signal.
Should I add an llms.txt file anyway?
It is a low-cost, low-risk experiment if you have spare time, and may have value as a forward-looking signal for agentic tools, but do not expect it to improve citations and do not prioritise it over real content and technical fixes.
Adam Clarke
Adam is a Chartered Marketer and Fractional CMO with over seventeen years in B2B and B2C marketing, and the founder of Rank Roadie. He writes about the messy overlap between search, AI and keeping humans accountable in the loop.