In short
Google Search does not require llms.txt and says the file does not affect visibility or rankings. It can be an optional index for other tools that explicitly support it.
What is llms.txt?
The llms.txt proposal describes a Markdown file that introduces a site and links to useful content for compatible systems. It is a proposal, not a universal requirement for AI crawlers. Support must be checked with the tool consuming it.
Does Google need it?
No. Google's AI optimization guidance says an llms.txt file is not needed for Google Search. Its June 2026 clarification states that the file does not positively or negatively affect visibility or rankings. It is fine to maintain one for other systems that use it.
Do not confuse llms.txt with robots.txt or an XML sitemap. Robots directives control crawler access for crawlers that obey them. Sitemaps provide discovery signals. An optional Markdown content index does not replace either.
When is it worth maintaining?
Use it when a specific assistant, documentation integration or internal workflow consumes it. Define that use first, then choose a short set of authoritative links. If no consumer is known, prioritize useful pages, internal navigation and accurate content before maintaining another file.
What should go in it?
Include a concise site description and grouped links to the current, canonical pages the consumer needs. Keep descriptions factual. Link to the original documentation or service page rather than duplicating a large body of text that will become stale. Avoid private information, obsolete offers and unsupported promises.
How do you keep it reliable?
Generate entries from published content where practical. Check that linked pages resolve, that descriptions match their destinations, and that redirects or excluded pages are removed from the inventory. At Troiana, the optional index is generated from site content so it can follow publishing changes.
How should you measure it?
Test whether the intended consumer actually reads the file and uses the linked information correctly. File access logs alone do not demonstrate citation, ranking or lead-generation benefits. Report those outcomes separately using the SEO and AI visibility workflow.
