llms.txt for an ecommerce store, and whether it does anything

An llms.txt file is a plain markdown file at the root of your site, at yourdomain.com/llms.txt, that tells AI tools what the site is and links to its most useful pages. For an ecommerce store it takes half an hour to write, and on Shopify or WordPress with Yoast it can be generated for you. It’s worth having. It’s also the smallest of the things that decide whether AI assistants recommend your products, and Google says plainly it doesn’t need one at all.

This is a build-along: what the format is, a worked example for a store, how to add it on each platform, how to check it, and where it fits among the jobs that actually move AI visibility.

What llms.txt is

The format was proposed by Jeremy Howard on 3 September 2024, and the specification site has been updated since. Its purpose is to give AI tools a short, clean summary and a list of links to read, instead of making them work through a site’s full HTML.

The format

The file is markdown. The specification makes only one part required: an H1 with the name of the site. After that it recommends a blockquote with a short summary, optional paragraphs of detail, and any number of sections under H2 headings, each a list of links with a short note. A section called Optional, by convention, holds secondary links a tool can skip.

Its companion files

The specification also suggests offering markdown versions of important pages, at the same address with .md added, and an llms-full.txt with the full text in one file. For most stores, the short llms.txt is enough.

Who uses it

The specification site notes that OpenAI, Anthropic and Google publish llms.txt files for their own developer documentation, and says Chrome’s Lighthouse checks sites for it. Publishing a file for your own docs isn’t the same as your search crawler relying on other people’s. None of the major assistants has said its shopping or search results depend on llms.txt.

A worked example for a store

Here’s a complete llms.txt for an example outdoor clothing shop. Swap in your own name, summary and pages; the shape stays the same.

# Harbour Outdoor

> Harbour Outdoor sells waterproof clothing and camping kit for UK walkers,
> with free UK delivery over £50 and 30-day returns.

We design our own jackets and trousers and stock a small range of
tents and stoves from other brands.

## Shop

- [Waterproof jackets](https://example.com/collections/jackets): men's and women's, sizes XS to XXL
- [Walking trousers](https://example.com/collections/trousers): waterproof and softshell
- [Tents](https://example.com/collections/tents): one to four person

## Help

- [Delivery](https://example.com/pages/delivery): UK and Europe, costs and times
- [Returns](https://example.com/pages/returns): 30 days, how to send items back
- [Size guide](https://example.com/pages/size-guide): body measurements by size

## Optional

- [About us](https://example.com/pages/about): who we are and where we make things

The heading and summary

The H1 is the shop’s name. The blockquote says what it sells, to whom, and the two facts shoppers ask about most, delivery and returns. Keep it to what’s true all year: a summary that mentions a sale will be wrong in a month.

The sections

Shop links to the main collections, with a note on what each contains. Help links to delivery, returns and sizing, because those are the questions an assistant is most likely to be asked about a store. Optional holds pages a tool can skip.

What to leave out

Individual product pages don’t belong here: there are too many, they change, and your sitemap and product feed already list them. The basket, checkout, account pages and search results don’t belong either. The file is a map to the pages that explain the business, not an index of everything.

Keep it honest

Everything in it should match the pages it links to. An llms.txt that promises next-day delivery when the delivery page says three to five days is a good way to have an assistant repeat the wrong promise to a customer.

Adding it on each platform

The file has to be served at the root of your domain, as plain text. How you get it there depends on the platform.

Shopify

Shopify lets a theme customise the files AI agents read. Its guide to agentic storefronts lists three Liquid templates you can add: agents.md.liquid, llms.txt.liquid and llms-full.txt.liquid. Adding llms.txt.liquid to the theme and writing the file in it serves your own version, and because it’s Liquid, it can pull in collection names and links rather than hard-coding them.

WooCommerce and WordPress

Yoast SEO can generate the file. Its help page says enabling the feature creates llms.txt in the site root and updates it weekly, and there’s a manual mode to choose exactly which pages it lists. Without Yoast, upload a text file named llms.txt to the site’s root folder.

Magento and custom builds

Put a static llms.txt file in the web root, the same folder that serves robots.txt, and check it loads at yourdomain.com/llms.txt. On a custom build, it can be generated from the same data that builds the sitemap, so it never drifts from the real pages.

Check it after deploying

Open yourdomain.com/llms.txt in a browser. It should show as plain text, not a store page or a 404, and every link in it should load. Watch for a redirect to the home page, which is what some platforms do with an address they don’t recognise.

Checking it

There’s no official validator, but the specification is short enough to check by hand, and a few checks catch nearly every problem.

• One H1. The file starts with a single heading: the site’s name.
• Real links. Every link is a full address and loads a page, not a redirect or an error.
• Short notes. Each link has a few words saying what’s there.
• Plain text. The server sends it as text, not as HTML wrapped in the theme.
• True today. Delivery, returns and ranges match what the pages say now.

The AI visibility checker on this site looks for the file as one of its sixteen checks, alongside the ones that matter more: whether AI crawlers are allowed in, whether the content loads without JavaScript, and whether the structured data parses.

Where it fits

The honest summary is that llms.txt is cheap, harmless and a small signal. Here’s where it sits among the things that decide whether AI assistants recommend a store.

What Google says

Google’s guidance on AI features is direct: “You don’t need to create new machine readable files, AI text files, or markup to appear in these features.” A page needs to be indexed and eligible for a snippet. For Google’s AI Overviews and AI Mode, llms.txt changes nothing.

What matters more

For ChatGPT, Perplexity and the rest: the search crawlers allowed in robots.txt, product details in the page’s HTML, structured data that parses, and product data complete enough to answer a shopper’s question. The Shopify walkthrough and what ChatGPT shopping means for your store cover those.

When to get help

If the file is the only AI work that’s been done on the store, the bigger gains are elsewhere. A health check on AI visibility reads the store the way these tools do and ranks what to fix first.