Answers the question: What are agents.md, llms.txt, UCP and WebMCP on my Shopify store, and do I need to edit them?
What each one is
| Item | Where to find it | What it does | Do you need to edit it? |
|---|---|---|---|
| agents.md | yourstore.com/agents.md | A description of the store for AI agents: how to find the product catalogue, where the UCP endpoints are, how to browse read-only, and a link to your policies. It also states that checkout needs the buyer’s approval | Normally no. Shopify generates it |
| llms.txt | yourstore.com/llms.txt | A plain-text summary for language models. By default it mirrors agents.md. Some apps extend it, for example with a list of collections and products | Not usually. Keep any additions accurate |
| UCP profile | yourstore.com/.well-known/ucp | The store’s Universal Commerce Protocol profile: supported versions, endpoints, capabilities and payment handlers. Since 4 September 2026, stores advertise version 2026-08-25 | No. Shopify maintains it |
| Agentic sitemap | listed in your sitemap | An extra sitemap that helps agents find products | No |
| WebMCP tools | built into Liquid storefronts | Tools an AI agent in the shopper’s browser can call to search the catalogue, use the cart and move to checkout. Live since 5 August 2026. Since 28 September 2026 the tools also cover checkout itself on eligible stores, including Shop Pay, so an agent can place the order with the buyer’s permission | No. Nothing to install |
Having the files is not the same as being ready
These files declare what your store can do. In our scans of Shopify stores, agents.md was the same boilerplate on every store we tested. We have also seen stores that had every file in place and still had no payment or delivery details in their product markup, and descriptions that gave an assistant nothing to quote. The files open the door. Your product data is what an assistant finds inside.
What to do instead
- Check that the files load. Open each address once.
- Spend your time on product titles, descriptions and options.
- If an app has extended your llms.txt, check that what it says is true.
Frequently asked questions
- Is llms.txt a ranking factor?
- There is no confirmed evidence that adding to llms.txt changes how an assistant treats your store. Think of it as a helpful summary, and keep it accurate.
- Can I edit agents.md?
- Shopify generates it for your store. Check Shopify’s documentation or ask Shopify before changing it.
- What is UCP?
- The Universal Commerce Protocol is an open standard that Shopify and Google announced in January 2026. It lets AI agents interact with a store’s catalogue and checkout in a common way.
- Do I need to do anything for WebMCP?
- No. Shopify switched it on for every Liquid storefront, and there is no app or setting. Browser agents have to visit your store before they can use the tools. Since 28 September 2026 those tools also cover checkout on eligible stores, including Shop Pay.