What Is llms.txt? Does Your Blog Need One?

Every few months a new file promises to get your site into AI answers. In 2026 it's llms.txt. I checked what it actually does, what Google says about it, and which well-known sites really publish one, then made a decision for this blog.

What llms.txt is

llms.txt is a plain Markdown file at the root of a website (/llms.txt). It was proposed by Jeremy Howard in September 2024 as a way "to provide LLM-friendly content". The idea: a language model or AI agent that needs to understand your site shouldn't have to wade through navigation, ads and scripts. It reads one short file that says what the site is and links to the pages worth reading.

The format is simple:

# Site name

> One-line summary of what the site is.

Optional notes, no headings.

## Section name

- [Page title](https://example.com/page/): what this page covers

## Optional

- [Less important page](https://example.com/other/)

Only the H1 is required. An Optional section, by convention, lists links an agent can skip when it's short on context.

Who reads it, and when

The proposal is clear that this is for AI tools working on demand, not for search engine ranking: "llms.txt information is instead used on demand, when an agent needs information about a topic while assisting a user." The authors write that they expected it "would mainly be useful for inference rather than training".

I've seen this work first-hand. When Claude Code fetched Anthropic's own documentation while I was researching these posts, the page told the agent: "Fetch the complete documentation index at: https://code.claude.com/docs/llms.txt". That's the real use case: an AI assistant reading your docs to help someone use your product.

What Google says

Google's documentation on AI Overviews and AI Mode is unambiguous:

"You don't need to create new machine readable files, AI text files, or markup to appear in these features."

It adds that there's "no special schema.org structured data that you need to add", and that to appear as a supporting link "a page must be indexed and eligible to be shown in Google Search with a snippet. There are no additional technical requirements."

So an llms.txt file won't get you into Google's AI answers, and not having one won't keep you out.

Which sites actually publish one (I checked 23)

On 7 November 2026 I requested /llms.txt from 23 well-known sites in blogging, SEO, hosting and developer tools. This is what came back:

That's 13 of the 21 sites that gave a clear answer. Three patterns stand out:

1. Developer platforms adopted it first. Anthropic, Stripe, Cloudflare and Vercel all publish one, because their users increasingly ask AI assistants how to use their APIs.
2. SEO plugins are adding it automatically. Two of the biggest files, on WPBeginner and Cloudways, say they were generated by All in One SEO. Those run to thousands of lines, which defeats the point of a short, curated file.
3. Several of the best-known SEO publishers don't bother. Ahrefs, Moz and Backlinko return 404. So does Google's own developer site.

Does your blog need one?

My answer for most bloggers: it's optional, and it won't move your rankings. Spend the time on pages that answer questions better than anything else in the results, because that's what gets cited in AI answers.

Add one if:

• AI tools read your site directly. A tutorial site, a tool or a product with documentation benefits the most.
• It's free to maintain. On a static site it can be generated at build time, so it never goes stale.
• You keep it short. Curate it. A file that lists 3,000 URLs is just a worse sitemap.

Skip it, or let it wait, if you'd have to update it by hand. An out-of-date llms.txt that points to deleted pages is worse than none.

What I did on this site

Until this week, blogginghouse.com/llms.txt returned a 404. I've now added one, because the second reason above applies: this site is built with Eleventy, so the file is generated from the same topic hubs as the navigation. It lists only the pages I'd want an AI assistant to read, each with its one-line description, and it updates itself every time I publish. It's about 20 lines of template.

You can read it at /llms.txt. It won't change how Google treats this site, and I'm not claiming it will. If I see evidence that AI tools use it, I'll update this post with what I find.

For more on how AI search actually picks its sources, see the AI Search guides. For how this site is built and generated, read how I build and run this website with Claude Code.