llms.txt vs robots.txt vs Google-Extended: What Actually Controls AI Crawlers in 2026?
SEOW3C Technical SEO Guide | Updated: October 21, 2026 | AI Search, Crawling & Content Governance Should you create an llms.txt file to improve visibility in ChatGPT and Google AI Overviews? Does blocking Google-Extended prevent Google from using your content in AI-generated search answers? And can robots.txt actually stop AI companies from training on your website? These questions have become increasingly important as publishers, developers, and SEO professionals attempt to balance organic search visibility, AI discovery, content licensing, and control over how their material is reused. The problem is that three very different mechanisms— llms.txt, robots.txt, and Google-Extended —are frequently discussed as if they perform the same job. They do not. The key finding for 2026: Google's published guidance explicitly states that llms.txt is not needed for Google Search, including its generative AI features. Google Search does not use it as a special optimizat...