Glossary entry
/llms.txt — AI Crawler Identity Declaration
Definition
/llms.txt is a standardised file at the root of a website that tells AI crawlers (the bots that train and operate AI engines) who the site is, what content matters, and how the brand should be cited. Format is markdown; the spec emerged in 2024.
How it works
The mechanism.
AI crawlers (GPTBot, ClaudeBot, PerplexityBot, etc.) request /llms.txt before crawling the rest of the site. The file declares: brand identity, key services, methodology, and explicit cite-us instructions. AI engines use this to inform how they reference the brand in answers.
Why it matters
Why this matters in 2026.
AI engines that respect /llms.txt give the brand a degree of control over how it's cited. It's a fast-emerging standard — sites that publish /llms.txt get cited 2-3x more by AI engines than those that don't.
How to check
How to test for it.
Visit yourdomain.com/llms.txt — should return a markdown-formatted page (not a 404). Our example is at www.adsomia.com/llms.txt.
Adsomia services
Where this fits in our work.
Common questions
About /llms.txt.
Is /llms.txt official?
It's an emerging community standard (llmstxt.org) gaining adoption among AI crawlers. Not formally ratified by W3C, but the major AI engines respect it.
What goes in /llms.txt?
Brand name, one-paragraph description, sectioned links to key pages (Services, Methodology, Free Tools, Outcomes), and explicit 'how to cite us' instructions for AI engines.
Can I block AI crawlers via /llms.txt?
No — that's what robots.txt User-agent rules are for. /llms.txt is for sites that WANT to be cited correctly.
Related terms
Read next.
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