What is llms.txt?

llms.txt is a proposed standard (see llmstxt.org) that helps AI-powered search engines and large language models understand your website. While robots.txt controls crawler access, llms.txt tells AI systems what your site is about, which pages are most important, and how to accurately represent your content.

As AI search engines like ChatGPT, Perplexity, Claude, and Google's AI Overviews become more prevalent, having an llms.txt file helps ensure your content is properly understood, cited, and ranked by these systems.

Where to place llms.txt

Upload the generated file to the root of your website at https://yourdomain.com/llms.txt. Some sites also provide a more detailed version at /llms-full.txt with additional content for AI systems that support longer context.

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Frequently asked questions

What is the difference between robots.txt and llms.txt?+

robots.txt controls which crawlers can access your site and which pages they can crawl. llms.txt is complementary — it doesn't control access but provides structured information about your site's purpose, key pages, and how AI systems should understand and cite your content.

Do all AI crawlers support llms.txt?+

llms.txt is an emerging standard and adoption is growing. Even if not all AI systems read it yet, having one signals to any system that does check it that you've thoughtfully prepared your content for AI indexing. It's a forward-looking investment in your GEO strategy.

How can I check if a site has an llms.txt?+

You can manually check by visiting yourdomain.com/llms.txt. Or install the free Lumina Chrome Extension which automatically checks for llms.txt and llms-full.txt on any page you visit, with a detailed report in the Crawler tab.

Check llms.txt on any site instantly

The Lumina extension checks for llms.txt, verifies AI crawler access via robots.txt, and tracks AI traffic — all in one click.

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