llms.txt is a simple text file placed at the root of a website. Its purpose is to help large language models understand what your site is about, what it does, and what content LLMs are allowed to use in their responses. The idea comes from robots.txt logic, adapted for the age of AI search engines.
We placed it on 12 client websites and spent the next three months measuring whether ChatGPT, Perplexity, Gemini, and Copilot mentioned our clients more frequently or differently than a control group. The methodology was imperfect — creating a clean control group is hard when content and other factors also change. But we gathered enough evidence to draw several conclusions.
The short answer: llms.txt alone is insufficient as a GEO strategy. The long answer covers which factors in our data correlated with higher LLM citation rates, and why structured content and digital PR mattered more than the file itself.
Full article coming soon.