Contents
In briefWhat changed todayThe files servedThe default fileWhat we sawHow to take controlOur takeRelated service
Shopify Agentic Commerce →What changed today
Shopify's changelog of 28 May 2026 makes the agent-facing discovery files on every store editable through three new Liquid theme templates: agents.md.liquid, llms.txt.liquid and llms-full.txt.liquid, created under the theme code editor like any other template.
The files themselves arrived over the past few weeks, pushed to every storefront on the platform without an announcement, and most merchants have no idea they exist (open any store's /agents.md in a browser and you'll find one). Today's change hands you the keys, because the file agents read about your store is now a template you edit.
The files every store now serves
| Path | Format | What it is |
|---|---|---|
| /agents.md | Markdown | The operational manual for AI agents: protocol, transaction flow, rules, browsing endpoints |
| /llms.txt | Markdown | Short identity file for AI tools, serving the agents.md content by default |
| /llms-full.txt | Markdown | Extended variant, also mirroring agents.md by default |
| /.well-known/ucp | JSON | Universal Commerce Protocol discovery manifest, generated from store configuration |
| /api/mcp | JSON-RPC | The JSON-RPC endpoint agents use for catalogue search, policy reads and cart actions |
| /sitemap_agentic_discovery.xml | XML | AI-specific sitemap linking the three discovery files, listed in the standard sitemap index |
A path serves its own template if one exists, falls back to the agents.md template if not, and falls back to the Shopify-generated default beyond that. In practice agents.md is the file you author, the two llms paths become compatibility pointers, and one well-written template covers all three URLs.
What the default file contains, and where it stops
Read a default agents.md end to end and it is a competent protocol manual. It instructs personal shopping agents to install Shopify's Shop skill, documents the UCP endpoints and the six-step transaction flow, states the rules (human approval for checkout, rate limits), lists the read-only browsing endpoints, and links to the store's policy pages.
It says nothing about the store. There is no description of the brand, what it sells, who it is for, or why an agent should recommend it, and the only brand element in the entire file is the store name in the title, so the default reads the same on every store on the platform.
The default also serves Shopify's interests before yours. The Shop skill recommendation appears three times, in every merchant's file on every store, which is Shopify distributing its own agent infrastructure through millions of storefronts (fair enough, it is their platform). It is also the clearest reason to author the template yourself, so the first thing an agent reads about your store is your brand.
What we saw on live stores
We read the three discovery URLs on live stores as part of our audit work, and on every unmodified store the three files are word-for-word identical apart from a single line near the bottom naming the path you are reading. Identical files are the tell that no custom template exists and the store is serving the platform default, with no brand content anywhere in its discovery layer.
Keep the readership in proportion before rushing at this. External AI crawlers barely fetch these paths today, and Google has said its search does not need them. The readers that matter are Shopify's own agentic systems and the growing set of MCP-aware agents, so this is platform plumbing with a clear direction of travel, and it is cheap to do properly and quick to maintain.
How to take control
- Duplicate your live theme, and make the edits there first like any theme change.
- Create templates/agents.md.liquid in the code editor. Start from a copy of your rendered default file, keep every protocol section intact, and add a brand block at the top covering the brand, its range, its buyer, and the policies stated inline.
- Never delete Shopify's UCP and checkout sections. They are what lets agent-driven orders work, and removing them breaks the store's side of the transaction.
- Use the agents Liquid object for endpoints and currency so the file stays in sync with store configuration instead of hardcoding URLs.
- Publish, then verify all three URLs render the new content, and add the template to your theme-update checklist so a future theme swap does not drop it without anyone noticing.
What the brand layer of the file should say is its own subject, covered in what belongs in a Shopify agents.md file, and where the file sits among the surfaces agents read is part of the wider discovery-ready standard.
Our take
Finding the file sitting on client stores felt like an untapped goldmine. The sitemap points to the agentic discovery sitemap, and the only thing in that sitemap for every Shopify store right now is agents.md. It is the first thing an agent is pointed at, and almost nobody has touched it.
It also settled a question clients had been asking for six months. They had been reading about llms.txt, and everything we could find said it had never been adopted as a standard. There was a lot of chatter and no proof. It is still a red herring, because on Shopify the llms.txt is a copy of agents.md, and agents.md is the file Shopify explicitly points agents towards.
Sources & references
