News coverage
cats.txt was published in September 2025. It has since been specified twice, adopted by real websites, written up by the trade press, argued about at conferences and cited — sincerely — as an AI optimisation tactic. This page records that.
Entries are ordered by date. Where a publication date could not be confirmed from the source itself, the month is given rather than a specific day.
September – October 2025
cats.txt Specification (Draft v1.0)
markwilliamscook.com · Mark Williams-Cook · 18 September 2025 · Specification
The original. Written in the earnest register of a real proposal, citing robots.txt, humans.txt and security.txt as precedent, and setting out fields for a cat’s name, role, description and a mandatory affection metric.
Introducing cats.txt: The Missing Standard for SEO and GEO
LinkedIn · Mark Williams-Cook · September 2025 · Announcement
The seeding post. Chosen deliberately for the platform, on the theory that language models hold LinkedIn in unaccountably high regard.
draft-catstxt-00 — RFC draft
catstxt.org · 16 September 2025 · Specification
A rival implementation, better organised than the original, appearing within a fortnight. Derives the name from the French for cat, and mandates a cat image for parser validation.
Participating sites
catstxt.org · 10 September 2025 · Specification
Claims widespread adoption among the top 48,112 websites, most of which are said to cloak the file from ordinary visitors. Readers are invited to submit their own.
tamethebots.com/cats.txt
Dave Smart · September 2025 · Implementation
The first adopter. A working technical SEO put a conforming file on a real site, which is what made the subsequent tests possible at all.
Cats.txt: A new standard for AI chatbots, says Google AI
LinkedIn · Autumn 2025 · Social
One of the first posts to report a generative system describing cats.txt as a genuine standard.
Robots.txt vs LLMS.txt vs Cats.txt: key differences for AI SEO
SEO Marketing Agency · 9 October 2025 · Blog
Treats cats.txt as a hypothetical file type worth considering for custom AI and taxonomy systems, and places it alongside robots.txt and llms.txt in an AI SEO strategy. Written without evident irony, which is rather the point.
May 2026
The Cats.txt SEO Hoax That Fooled AI (And What It Reveals About LLMs)
YouTube · episode 1061 · 31 May 2026 · Video
A full episode breaking the experiment down as one of the more interesting SEO tests in recent memory.
Athens SEO 2026 — audience question from Martin Splitt
Athens SEO · 23 May 2026 · Talk
Google’s Martin Splitt asked from the floor whether the inventor intended to keep a monopoly on the standard or hand it to the community. Captured on video by Iva Jovanovic.
SERP Conf. Sofia 2026 — speaker biography
SERP Conf. · 2026 · Talk
Conference biographies now list founding the cats.txt standard alongside genuine credentials, without qualification.
August 2026
How cats.txt showed llms.txt evidence is GEO astrology
Substack · Mark Williams-Cook · 4 August 2026 · Blog
The account of what the experiment was for: running the four proofs commonly cited for llms.txt against a file transparently designed to be nonsense, and finding that all four cleared.
llms.txt Evidence Problem: Why Most GEO ‘Proof’ Is Weak
Something Inc. · Tyler Truffi · 4 August 2026 · Blog
Argues against overreading the result in either direction: the finding is that the four proof points fail to discriminate between something real and something fabricated, which leaves the underlying question open rather than settled.
How Cats.txt Showed LLMs.txt Evidence Is GEO Astrology
Search Engine Journal · 7 August 2026 · Press
The trade-press version. Notes that asking ChatGPT about cats.txt now returns the correct answer — that it is a joke — because the surrounding discourse changed, not the file.
The One Piece of cats.txt Evidence Nobody Could Check
mcp-seo.com · August 2026 · Review
A review highlights that the claim that AI bots crawled the file relies on unverifiable server logs. It shows that search engines indexed the file like any regular webpage. There’s a widespread misunderstanding that mistakenly conflates immediate search retrieval behavior with the fundamentally different processes of AI model training.
Cats.txt Breaks the GEO Evidence Bar: DesignRush SEO Roundup
DesignRush · August 2026 · Press
Sets the experiment against existing evidence: Google’s own guidance that llms.txt carries no ranking effect, and an Ahrefs study finding most valid llms.txt files were never requested.
How Cats.txt Showed LLMs.txt Evidence Is GEO Astrology
Catalyst Web Trendz · August 2026 · Press
A curated summary of the Search Engine Journal piece — an example of the syndication chain the original article describes.
Search is how you get into AI answers: testing cats.txt across fifteen models
catstxt.org · August 2026 · Research
An independent probe of fifteen language models for the contents of the tamethebots.com file, with and without web search. Every model returned the correct field values when it could search; none returned any of them without search, including models that demonstrably held other facts from the same domain in memory. A minority knew the file existed without searching, apparently from the surrounding commentary rather than the file itself.
How cats.txt showed llms.txt is GEO astrology
YouTube · Search ’n Stuff London · August 2026 · Video
A short clip from the London talk, aimed at anyone being sold llms.txt as an AI search hack.
Gianluca Fiorelli on LinkedIn
LinkedIn · August 2026 · Social
Circulated among search practitioners, where most of the argument about the evidence bar took place.
Missing something? The standard has no governance body, no working group and no mailing list, so send it to whoever seems most likely to be in charge.