What is llms.txt?
llms.txt is a proposed Markdown file, placed at a site's root as /llms.txt or under a section such as /docs/, that gives AI tools a short summary of the site and links to its most useful pages. Google Search does not use it.
Cited from the66th.com/glossary/llms-txt
How llms.txt works
Jeremy Howard proposed the file on llmstxt.org on September 3, 2024. The proposal argues that web pages carry navigation, ads and scripts that make them hard for an AI tool to read, so the file gives an AI agent a short, clean overview in one place. It is written in Markdown, a plain-text format where # marks a heading and - marks a list item.
The proposal sets a fixed order: a title, which is the only required part, then a short summary in a blockquote, then optional notes, then sections of links with short notes. A section called Optional holds links an agent can skip. The proposal expects the file to be read while an AI tool answers a question, more than for training.
# Example Plumbing
> Licensed plumber serving Calgary since 2009. Water heaters, drains and emergency repairs.
## Services
- [Water heater replacement](https://example.com/water-heater-replacement/): Tank and tankless units
- [Emergency plumbing](https://example.com/emergency-plumber/): Same-day service areas and hours
## Optional
- [About us](https://example.com/about/)Where Google stands on llms.txt
Google answered the question in its guide to optimizing for generative AI features on Google Search, which Google announced on May 15, 2026. The guide says you do not need to create machine-readable files, AI text files, markup or Markdown to appear in Google Search, including its AI features, because Google Search itself does not use them.
A note Google has since added to the guide says that creating an llms.txt file for other services is fine, and that doing so will neither harm nor help a site's visibility or rankings in Google Search, because Google Search ignores the file.
What it means for your business
For Google, including AI Overviews and AI Mode, an llms.txt file changes nothing. Ranking and being linked there come from SEO: indexed pages that answer buyer questions well.
The file can still help where AI agents read a site's documentation, such as a software company whose developer docs coding assistants fetch. For a local service business, it sits low on the list. Our AI search optimization work starts with the pages that AI answers already draw on.
Common mistakes
- Expecting llms.txt to lift Google rankings or win a place in AI Overviews. Google says the file neither helps nor harms visibility in Google Search.
- Using llms.txt to control AI crawlers. It gives no permissions; the proposal itself says robots.txt and llms.txt have different purposes, so access rules stay in robots.txt.
- Letting the file go stale. Links to moved or deleted pages send an agent to errors, so update it when the pages it lists change.
Related terms
Sources: llmstxt.org, Jeremy Howard, The /llms.txt file, 3 September 2024, updated 10 August 2026; Google Search Central, Optimizing your website for generative AI features on Google Search, 10 July 2026; Google Search Central Blog, John Mueller, A new resource for optimizing for generative AI in Google Search, 15 May 2026.