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What is llms.txt, and do you need one?
In this article
llms.txt is a plain Markdown file at the root of your site, at yoursite.com/llms.txt, that tells AI tools what your site is and where its most useful pages are. Jeremy Howard proposed it on 3 September 2024, at llmstxt.org, as a standard way to hand a language model a short, clean map of a site instead of making it read every page.
Do you need one? Google's guidance, clarified on 15 June 2026, says Google Search ignores llms.txt files, so one neither helps nor hurts your rankings there, and that keeping one for other services that use it is fine. So it's a cheap file for the AI agents and tools that do read it, and it won't move your rankings. Everything below was checked on 23 October 2026.
- The only required part is an H1 with your site or product name. A one-line summary in a blockquote and lists of key pages under H2 headings are optional, and most files have them.
- Google says its Search ignores llms.txt. Treat the file as help for AI tools, not a ranking signal.
- Vercel and Anthropic both serve one. Open yoursite.com/llms.txt in a browser to see whether you do.
What goes in the file
The llmstxt.org proposal sets the order. A file that follows it reads top to bottom like a short briefing.
| Part | Required? | What it holds |
|---|---|---|
| H1 | Yes, the only required part | The name of the project or site |
| Blockquote | Optional | A short summary of what it is |
| Detail | Optional | Paragraphs or lists with no headings, for anything the summary leaves out |
| H2 sections | Optional | Lists of links, each written as [name](url) with an optional note after a colon |
| Optional | Optional | An H2 named Optional, by convention, for secondary pages an agent can skip when it needs less |
The proposal also suggests a clean Markdown version of each page at the same address with .md added, so an agent can read the page without the HTML around it.
How to write one
- Start with an H1 that is your product's name, exactly as your homepage writes it.
- Add one blockquote line saying what the product is and who it's for.
- Under H2 headings such as Docs, Pricing and Product, list your key pages as Markdown links with a short note each.
- Put the pages that matter less under an H2 called Optional.
- Save it as llms.txt at your site root, on the same domain as your homepage, served as plain text.
- Keep AI crawlers allowed in robots.txt. An llms.txt can't help an engine you've blocked from reading the site.
- Update it when your key pages or your positioning change, so it never says something the site doesn't.
Check your own site
Open yoursite.com/llms.txt in a browser. If you see your Markdown, it's live. If you see your 404 page or your homepage's HTML, it isn't, because a file that comes back as a web page isn't an llms.txt. The free llms.txt checker does the same fetch for you and, if there's no file, writes one from a few details you give it.
Run the free llms.txt checker →Who serves one
Vercel's file opens with "# Vercel" and a one-line blockquote, which is the format exactly. Anthropic's developer docs serve one at platform.claude.com/docs/llms.txt and link a longer llms-full.txt beside it. Cloudflare's opens with a block of front matter before its H1, so even large sites bend the format. AfterLaunch serves one at afterlaunch.io/llms.txt.
Where it fits
An llms.txt is a small piece of being readable by AI. What decides whether an assistant names you is mostly elsewhere: whether its crawlers can reach your pages, and whether other sites describe you clearly. AfterLaunch's free deep scan asks ChatGPT, Gemini, Google AI Overviews and Perplexity the questions your customers ask and shows who they name. After 14 free days with no card it's $149 a month to keep that read weekly and get the next growth move drafted in your voice.
Run the free AI crawlability checker →What is llms.txt used for?
It gives AI tools and agents a short Markdown map of your site: its name, a one-line summary and links to the pages worth reading. Jeremy Howard proposed it at llmstxt.org on 3 September 2024.
Does llms.txt help with Google rankings?
No. Google's guidance, clarified on 15 June 2026, says Google Search ignores llms.txt files, so one neither helps nor harms your visibility there. Google also says it's fine to keep one for other services that use it.
What's the difference between llms.txt and robots.txt?
robots.txt tells crawlers what they may fetch. llms.txt tells AI tools what your site is and which pages matter. Keep both: an llms.txt can't help a crawler that robots.txt blocks.
What is llms-full.txt?
A companion file some sites publish beside llms.txt, carrying the full text of their pages rather than a map. Anthropic's developer docs link one from their llms.txt.
- llmstxt.org, The /llms.txt file, Jeremy Howard, 3 September 2024, read 23 October 2026
- Google Search Central, AI optimisation guide, read 23 October 2026
- Google Search Central, documentation updates, 15 June 2026 entry on llms.txt, read 23 October 2026
- Vercel, llms.txt, read 23 October 2026
- Anthropic developer docs, llms.txt, read 23 October 2026
- Cloudflare, llms.txt, read 23 October 2026
An llms.txt is the small part. The deep scan asks ChatGPT, Gemini, Google AI Overviews and Perplexity the questions your customers ask, and shows who they name. Free, no card.
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