llms.txt

llms.txt is a plain text file, proposed as a new convention and placed at yoursite.com/llms.txt, meant to give AI systems a quick, clean summary of a site: what the business does, its key pages, and the facts worth getting right. The idea mirrors robots.txt and sitemaps, a small file with a specific, narrow job, except this one is aimed at language models instead of search crawlers.

It is a young idea, not an established standard the way robots.txt is. Some sites have adopted it. No major AI system, ChatGPT, Google’s AI answers, Perplexity, has publicly confirmed that it reads and relies on the file to generate answers. It is a reasonable bet, not a guaranteed lever.

Why it matters to you

More of your customers are asking AI tools questions before they ever open your website: what a service costs, whether a business does a particular thing, how it compares to another option. If the AI’s understanding of your business is wrong or outdated, it can quietly cost you leads who never even reach your site to correct the record.

llms.txt is one small piece of a wider effort, sometimes called AEO or AI search optimisation, aimed at making sure the facts an AI system might repeat about your business are the accurate, current ones, not something scraped from an outdated directory.

How I use it

I treat it as a cheap addition, not a strategy on its own. Where it makes sense, I add a short, accurate summary of the business, its services and its most important pages, kept current the same way the rest of the site is. It takes very little effort to maintain once it exists.

The real work happens elsewhere: clean structured data that describes the business unambiguously, content that answers real questions plainly, and a consistent, accurate presence across the web that any AI system pulling from multiple sources would agree on. llms.txt supports that work. It does not replace it.

What it looks like in practice

If it exists on a site, it is a short plain-text document, a few sentences about the business and a list of its key pages, sitting quietly at a predictable address. Nobody visits it directly except the occasional curious developer.

Whether it changes anything measurable is genuinely unclear right now, and I say that plainly rather than overselling a new file as a guaranteed win. It is worth having because it costs almost nothing and might help. It is not worth reorganising a site’s whole content strategy around.