Contents
What changed todayThe files servedThe default fileWhat we sawHow to take controlRelated 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 quietly over the past few weeks, pushed to every storefront on the platform without an announcement. Most merchants have no idea they exist, and you can check any store right now by opening its /agents.md in a browser. Today's change matters because it hands over the keys: the file agents read about a store is now a surface the merchant controls.
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 |
The one behaviour to understand is the fallback chain. 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 that makes agents.md the canonical authoring surface, with the two llms paths demoted to compatibility pointers, and it means one well-authored 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.
What it does not contain is 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. The default reads identically on every store on the platform, because it is the same file everywhere.
Note whose interests the default serves. The Shop skill recommendation appears three times, through every merchant's file, on every store, which is Shopify distributing its own agent infrastructure through millions of storefronts. That is a reasonable platform play, and it is also the clearest reason to author the template yourself: the first thing an agent reads about your store should be 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. Cheap to do properly, quick to maintain, and on the right side of where Shopify is consolidating.
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 silently drop it.
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.
Sources & references
