What Is llms.txt? A Practical Guide for 2026
A plain explanation of llms.txt, what it can and cannot do for AI search, and how to build one.
Key takeaways
- 01llms.txt is an optional, plain-text file that points AI tools to the most useful pages on a site.
- 02Google Search does not use llms.txt for ranking; treat it as a helper for AI tools, not a ranking lever.
- 03Keep the file short, accurate and linked to pages that are already indexable.
- 04Check that robots.txt lets the AI crawlers you want reach the pages the file links to.
What llms.txt is
llms.txt is a plain-text file at the root of a site, usually at /llms.txt. It gives large language model tools a short map of the site: what the business does, and which pages hold the most useful information. The format is a convention, not an official standard for search engines.
What it does and does not do
- It can help AI tools find your best pages when they build answers about your business.
- It does not guarantee citations. AI tools decide what to cite from many signals.
- Google Search does not use it for ranking. Google's guidance on search still centres on indexable, useful pages.
Treat it as one small part of a wider AI search plan, alongside clear answers, structured data and accurate facts.
How to write one
- Start with a one-paragraph description of the business, in plain language.
- List the most important pages under clear headings, such as Services, Guides and Products.
- Give each link a short, accurate label. Do not stuff keywords.
- Keep it short. A long list of thin pages reduces the value of the file.
- Link only to pages that return 200 and are allowed in robots.txt.
Check your robots.txt
If robots.txt blocks an AI crawler, it cannot read the pages that llms.txt links to. Check that the crawlers you want, such as GPTBot, ClaudeBot and PerplexityBot, are allowed to fetch your key pages. Blocking them is a policy choice; make it deliberately.
How to check your file
- Open the file in a browser and confirm it loads with a 200 status.
- Click every link and confirm each one resolves.
- Ask an AI tool a question about your business and see which pages it cites.
Frequently asked questions
Do I need llms.txt? No. It is optional. If you publish one, keep it accurate and up to date, and do not treat it as a substitute for good pages.
