Does llms.txt work?

llms.txt is a file you put at the root of your site, like robots.txt, to give AI models a short summary of your site in plain text. It's been widely recommended as a way to get noticed by ChatGPT and other assistants. The short answer: no major assistant has said it uses the file, and the one large study we know of found no link between having the file and how often a site gets cited.

What it is

llms.txt was proposed in September 2024 by Jeremy Howard of Answer.AI. It's a Markdown file at /llms.txt with your site's name, a one-line summary, and lists of links to your most useful pages, each with a short description. The idea: a model with limited room can read one clean file instead of crawling pages full of menus and scripts.

What the assistants say

• Google: for AI Overviews and AI Mode, Google says "you don't need to create new machine readable files, AI text files, or markup to appear in these features."
• OpenAI: its crawler documentation explains how to appear in ChatGPT search through robots.txt and OAI-SearchBot. It doesn't mention llms.txt.
• Anthropic: its crawler documentation covers robots.txt for ClaudeBot, Claude-SearchBot and Claude-User. It doesn't mention llms.txt either.

None of them has said its assistant reads llms.txt when it answers a question.

What the data says

SE Ranking looked at about 300,000 domains and how often each was cited in AI answers. About 10% had an llms.txt file. It found no significant correlation between having the file and how often a domain was cited. That doesn't prove it can never help, but there's no sign that it does.

Analyses of AI crawler logs disagree on how often crawlers even fetch the file: some report they almost never do, others see occasional requests. Either way, fetching a file isn't the same as using it to answer.

Where it might help

llms.txt is most useful for developer documentation. Coding tools and agents that are pointed at a docs site can use it as a map, and many developer docs publish one for that reason. If you sell software with public docs, it's reasonable to add one.

For a local business, a shop or a service website, there's no evidence it changes whether ChatGPT recommends you.

Should you add one?

It's harmless and quick, so if your site builder makes it a checkbox, go ahead. We publish one ourselves. But don't expect it to change anything, and don't pay anyone to write it.

Time spent on these does more:

• Allowing the search crawlers in robots.txt, especially OAI-SearchBot for ChatGPT
• Making sure your pages show their text without needing JavaScript
• Pages that answer what customers ask, in plain words
• Getting onto the lists, review sites and threads the assistants cite

All of that is in the AI visibility checklist.