llms.txt is a proposed standard designed to structure web content in plain Markdown, making it easier for large language models (LLMs) to understand and index documentation efficiently. This format, served at the /llms.txt path on websites, outlines crucial content in a simplified manner, enhancing how documentation appears in AI-generated answers. While initially adopted by a niche group following its proposal by Jeremy Howard in 2024, its use expanded significantly after Mintlify implemented it across all hosted documentation sites, influencing major companies like Anthropic and Cloudfare. However, some SEO experts remain skeptical, as llms.txt focuses on optimizing AI comprehension rather than traditional search engine visibility. The standard's advocates argue that it improves user experience by providing faster, more accurate AI-driven suggestions and reducing token usage in AI applications. Despite criticism, llms.txt is gaining traction, particularly among developer-focused companies, for its potential to facilitate AI-native documentation and improve interactions with coding assistants.