How AI Search Works
1
Attention Is All You Need: The Google Paper That Accidentally Ended Google's Search Monopoly.
On June 12, 2017, eight researchers at Google Brain published a 15-page paper. It accidentally made Google's own search business obsolete.
2
How Large Language Models Actually Work: Tokens, Context Windows, and Why Your Content Gets Ignored.
The answer to "how do I get cited by AI search?" is technical, not strategic. It's rooted in how large language models actually process information.
3
What Is RAG: the Only Thing That Matters for AI Search.
Once you see how Retrieval-Augmented Generation works, the rest of AI search visibility clicks into place. It's the mechanism that connects your content to every answer these systems produce.
4
The AI Search Race: ChatGPT, Gemini, Claude, Copilot, and Perplexity. A Technical Timeline.
The models, the milestones, and the architectural decisions that shaped every AI search product in market. A reference for anyone trying to make sense of where this came from.
5
How Google AI Overviews and AI Mode Actually Work: Why Your SEO Rankings Don't Guarantee AI Visibility.
AI Overviews aren't a ranking bonus layered on top of existing positions. In May 2024, Google restructured how most people receive information. The blue links became supplementary.
6
How to Be Surfaced in AI Search: What the Platforms' Own Documentation Actually Says.
Most GEO content produces a list of tactics and implies they work across all platforms. This article goes directly to what each platform has actually published about how its own system works.
7
Why the Bing AI Performance Report Is the Most Underused Tool in GEO.
Microsoft's Bing AI Performance report is the only first-party citation dashboard from any AI search platform. Most people working in GEO aren't using it.
8
The GEO Documentation Gap: Why Three Platforms Haven't Told You How to Rank in Their Systems.
Google published a guide. Microsoft published measurement tooling. Anthropic, OpenAI, and Perplexity have published nothing equivalent. Understanding why is more useful than waiting.
9
Constitutional AI vs RLHF: Why the Alignment Method Affects What Gets Cited.
ChatGPT is aligned with RLHF. Claude is aligned with Constitutional AI. These aren't interchangeable, and the difference affects what each model treats as trustworthy and citable.
10
Training Data Is the New Ranking Factor: The Common Crawl AI Visibility Audit Explained.
Before RAG, before indexing, a site has to be reachable by the crawlers that feed AI training data. The Common Crawl AI Visibility Audit is the framework for checking that upstream layer.
11
Blocking AI Training Can Cost You Search: Cloudflare's September Defaults Explained.
Cloudflare split AI bots into Search, Agent and Training. Multi-purpose crawlers resolve to the most restrictive rule, so a training block can take your search visibility with it.
12
Google Finally Reports AI Visibility. It Still Won't Tell You What It's Worth.
Search Console's Generative AI report gives you impressions and nothing else. No clicks, no queries, and no split between AI Overviews and AI Mode. Here's how to use it honestly.
13
The AI Search Statistics Everyone Repeats, and Where They Actually Came From.
Gartner's 25% prediction rests on a survey of 299 people. The 14% AI Mode figure isn't Google's. AI traffic converts 3x, not 23x. The audit, and the method for running it yourself.
14
15
Schema Markup Doesn't Drive AI Citations. It Still Matters.
1,885 pages that added schema, against 4,000 matched controls, tested with difference-in-differences. The effect on AI citations was nil. Keep your schema anyway, and here's why.
16
The AI Browser Died. Now Agents Browse as Your Reader.
OpenAI shut down Atlas and moved agentic browsing into a Chrome extension. The winning model runs the agent inside your reader's session, using their logins, which breaks how most people think about blocking bots.
Writing  ·  Series: How AI Search Works  ·  Part 14 of 16

97% of llms.txt Files Are Never Read. Here's the Data.

llms.txt is the most confidently recommended tactic in GEO. Ahrefs checked 137,000 domains and found that 97% of the files received zero requests. Google's own documentation says you don't need one. Here's what the evidence actually shows, and what to do instead.

If you've been told to publish an llms.txt file, you've been told by someone who didn't check whether anything reads it.

The idea is reasonable enough on its face: a plain-text file at the root of your domain, listing your key content in a form that's easy for a language model to parse. A robots.txt for the AI era. It has been recommended in conference talks, sold as a deliverable, and shipped by default across entire hosting platforms. What it has not been is adopted by a single major AI provider.

The number that settles it.

Ahrefs ran the obvious experiment, which is to check server logs and see whether anyone actually requests the file.

97% of valid llms.txt files received zero requests. Ahrefs studied 137,000 domains through its Web Analytics data. Of the roughly 38,000 with a valid llms.txt file, 97% got not a single request for it during May 2026. Not from an AI assistant, not from an AI search bot, not from a crawler.

That's not a subtle signal that the tactic underperforms. It's the file sitting on the server, untouched, while people bill for having created it.

The reason is straightforward, and Ahrefs states it plainly: no major LLM provider currently supports llms.txt. Not OpenAI. Not Anthropic. Not Google. None of them has formally adopted it as part of their crawler protocol. A standard that nobody has agreed to implement is a proposal, not a standard.

Google has said so in writing.

You don't have to infer Google's position from crawl logs. It's in the documentation, in the AI optimisation guide revised on 10 July 2026.

Google's wording: "You don't need to create new machine readable files, AI text files, markup, or Markdown to appear in Google Search." The guide goes further and says that creating such files will "neither harm nor help your site's visibility or rankings."

Read that last clause carefully, because it's the fairest summary of the whole tactic. Publishing an llms.txt file isn't dangerous. It costs you a few minutes and a few kilobytes. It just doesn't do anything, and the confidence with which it gets recommended is wildly out of proportion to the evidence behind it.

A standard nobody has agreed to implement is a proposal.

Why the adoption numbers look better than they are.

You'll see adoption charts showing llms.txt spreading quickly, and they're accurate. They're also measuring something other than what they appear to measure.

A large share of that growth is platform-injected. When a hosting platform ships llms.txt across every store on its network, adoption jumps by tens of thousands of domains overnight without a single site owner deciding anything. The chart goes up. The number of people who chose the tactic doesn't move.

This is worth internalising as a general pattern, because it will happen again with the next proposed standard. Adoption counts measure what platforms ship by default. They tell you nothing about whether the thing works, and nothing about whether anyone on the other end is listening.

Where it does make sense.

There's a narrow case worth acknowledging, because blanket dismissals age badly.

If you publish developer documentation that people feed directly into coding assistants, a curated plain-text index of your docs has genuine utility. The consumer there isn't a search crawler discovering your file autonomously. It's a human pointing a tool at a URL you gave them. That's a real workflow, and some documentation sites support it well.

That is a different thing from an AI visibility tactic. It doesn't get you cited in AI Overviews, it doesn't affect what ChatGPT retrieves, and it isn't what the people selling llms.txt audits are claiming.

What to do with the hour you just saved.

Everything below has evidence behind it and is covered in more depth elsewhere in this series.

None of that is as satisfying as adding a file and ticking a box. It's the work that actually determines whether you get retrieved.

The broader point isn't really about llms.txt. It's that this field rewards confident recommendations far more than it rewards checking, and the checking is usually one search away. Ahrefs looked at server logs. Google wrote it in the documentation. Both were available to anyone who went looking before putting it in a deck.

Frequently asked

Does llms.txt actually work?

There's no evidence that it does. Ahrefs studied 137,000 domains and found that 97% of valid llms.txt files received zero requests during May 2026. No major AI provider has adopted it as part of their crawler protocol.

Does Google support llms.txt?

No. Google's AI optimisation guide states you don't need to create machine readable files, AI text files, markup or Markdown to appear in Google Search, and that doing so will neither harm nor help your visibility or rankings.

Do OpenAI or Anthropic read llms.txt?

Neither has formally adopted it as part of their crawler protocol. Claims that specific providers officially support it generally trace back to vendors with no primary source attached. Use robots.txt for crawler control instead, which they do respect.

Should I remove my llms.txt file?

There's no need. It causes no harm, costs almost nothing to host, and Google is explicit that it will neither help nor hurt. Just don't count it as AI visibility work or bill anyone for it as a deliverable.

Why do adoption charts show llms.txt growing fast?

Because a large share of that growth is platform-injected rather than chosen. When a hosting platform ships the file across every site on its network, adoption jumps without any site owner deciding anything. Adoption measures defaults, not effectiveness.

Is llms.txt ever useful?

In one narrow case: developer documentation that people paste directly into coding assistants. There the consumer is a human pointing a tool at a URL, not a crawler discovering the file. That's a documentation convenience rather than an AI search tactic.

Next in the series

llms.txt isn't the only widely recommended tactic with thin evidence behind it. Article 15 looks at what happened when someone tested schema markup properly. Read Article 15 →

SOURCES ↓
  1. Ahrefs, "What is llms.txt?" (137,000 domain study; 97% of valid files received zero requests), Ryan Law, 15 June 2026 - ahrefs.com/blog/what-is-llms-txt
  2. Google Search Central, "Optimizing for Generative AI Features on Google Search," revised 10 July 2026 - developers.google.com/search/docs/fundamentals/ai-optimization-guide
  3. Cloudflare, "Bot Preference Sync," 21 August 2026 - blog.cloudflare.com/bot-preference-sync
  4. Google Search Console Help, "Generative AI performance report (Search)" - support.google.com/webmasters/answer/16984139

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