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Glossary · Letting AI crawlers in

llms.txt

Also called llms txt, LLMs.txt, llms-full.txt

Definition

llms.txt is a proposed markdown file at a site's root that gives language models a short summary of the site and links to the pages most worth reading.

Updated 15 Sept 20262 sources, each checked3 min read

The idea

What it is

llms.txt is a plain markdown file that acts as a reading list for language models. Where a sitemap lists every URL for a search engine, llms.txt picks the handful of pages that explain what a product or project is, with a line on each, in a format a model can take in within a small context window.

It is a community proposal, not a standard with an enforcement body, and it controls nothing. It does not allow or block crawling; that remains the job of robots.txt. Its value is editorial: you decide which pages describe you, rather than leaving a model to infer it from whatever it happened to fetch.

The evidence

Why it matters

When an assistant describes your company, it works from what it can read quickly. A clear summary and a curated list of your key pages is cheap to publish and removes guesswork about pricing, positioning and what the product does.

Adoption is uneven even among the companies selling AI visibility. In our scan, about half of the vendors publish one, which makes it a small, visible way to look prepared. Treat it as good documentation hygiene rather than a ranking lever: whether a given engine reads it is that engine's decision.

The steps

How to do it

  1. 1

    Start with an H1 naming the site or product, then a one-paragraph blockquote saying what it is, who it is for and what it costs, in plain sentences.

  2. 2

    Add H2 sections of links, each written as a markdown link with a short note: product pages, pricing, documentation, and the pages that answer the questions buyers ask most.

  3. 3

    Put nice-to-have links under an H2 titled Optional, so an agent short on context knows what it can skip.

  4. 4

    Publish it at /llms.txt as plain text, link to real canonical URLs, and keep it in step with pricing and product changes, because a stale summary is worse than none.

  5. 5

    Validate the structure before publishing, and recheck it whenever key pages move.

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What goes wrong

Common mistakes

  • Dumping every URL from the sitemap into it, which defeats the point of a short, curated list.
  • Expecting it to block or allow AI crawlers. Access is controlled by robots.txt, which llms.txt does not change.
  • Assuming every AI engine reads it. It is a proposal, so check each vendor's own documentation rather than relying on it for visibility.
  • Letting the summary drift out of date, so a model repeats an old price or a retired product.
In practice

An example

The minimal valid file

Following llmstxt.org, a valid file can be as small as an H1 line with the product name, a blockquote summary underneath, and one H2 section called Docs containing markdown links with a short description after each. Everything beyond the H1 is optional in the specification.

Jeremy Howard, The /llms.txt file (llmstxt.org), 15 Sept 2026
Nearby terms

Not to be confused with

robots.txt
robots.txt tells crawlers what they may fetch and is widely honoured. llms.txt suggests what a model should read first and grants or blocks nothing.
XML sitemap
A sitemap lists every indexable URL for search engines. llms.txt lists a curated few with human-readable notes, written for a model with limited context.
Original data

Do AI search vendors let AI crawlers in?

VendorNames AI crawlersBlocks any AI crawler site-widePublishes llms.txt
Veritas (ours)getveritas.ioYesNoYes
Semrushsemrush.comNo, wildcard ruleNoYes
Frasefrase.ioYesNoYes
Profoundtryprofound.comNo, wildcard ruleNoNo
Jasperjasper.aiYesNoYes
Surfersurferseo.comNo, wildcard ruleNoNo
Writesonicwritesonic.comNo, wildcard ruleNoYes
Otterly.AIotterly.aiUnknownUnknownUnknown
Scrunchscrunch.comNo, wildcard ruleNoYes
AthenaHQathenahq.aiNo, wildcard ruleNoYes
GEOforgegetgeoforge.comNo, wildcard ruleNoNo
Passionfruitgetpassionfruit.comYesNoYes
Ahrefsahrefs.comNo, wildcard ruleNoNo
SE Rankingseranking.comYesNoNo
Peec AIpeec.aiNo, wildcard ruleNoNo

How we checked. One fetch of each domain’s /robots.txt and /llms.txt on 15 September 2026. For each AI agent we read the group that names it, or the wildcard group if none does, and recorded whether the whole site is disallowed. An llms.txt counts when the path returns a plain-text file rather than an HTML page.

  • A single fetch on one day with one user agent. Vendors change these files without notice.
  • robots.txt states a policy. It does not show what a site actually enforces at the server.
  • Where a server refused our request, the row is marked unknown rather than guessed.
Checked

Sources

  1. 1Jeremy Howard, The /llms.txt file (llmstxt.org) read 15 Sept 2026
  2. 2Veritas crawler policy scan of 15 AI search vendors read 15 Sept 2026

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