SKU.md · stable knowledge
A merchant-owned root catalog entry and optional source-backed product knowledge. It does not claim current commercial state.
SKU.md 1.0.0-beta
Give shopping agents a clear path to your official catalog.
Publish one small Markdown file at /sku.md. Add source-backed product knowledge only when it helps. Live price, inventory, shipping, and checkout stay with live commerce systems.
Why SKU.md?
One small, merchant-owned file gives agents an official entry point to the public catalog without copying the catalog into a new system.
Optional per-item documents can add stable product facts when each fact is backed by a visible public source.
Stable knowledge stays separate from changing price, inventory, shipping, offer, and transaction state, which remain with live commerce systems.
Publishing SKU.md does not guarantee platform adoption, citation, ranking, recommendation, visibility, or sales.
One commerce stack, three different jobs
Use each layer for the information it can truthfully own, and hand changing state to the live authority.
Feed / Catalog · live products and offers
The current product set, market-specific offers, price, inventory, availability, shipping, and fulfillment state.
UCP / ACP · transactions
Transaction capabilities and state such as cart, checkout, payment, authorization, and orders.
A bounded responsibilities map
These surfaces complement one another. None is evidence that a platform has adopted SKU.md.
robots.txt
Crawl access
Expresses crawler access preferences; it is not a catalog, knowledge source, or transaction interface.
Sitemap
URL discovery
Lists site URLs and update hints for discovery; it does not describe product facts or live offers.
llms.txt
Curated document pointers
Points readers to selected site documents; it does not replace the merchant catalog or authorize transactions.
Product JSON-LD
Page-level structured data
Describes a product on an HTML page for structured-data consumers; freshness depends on that page.
Merchant Feed
Live products and offers
Carries platform-specific product, offer, price, availability, shipping, and market data.
WebMCP
Page-level interaction
Exposes bounded tools from a web page when supported; it does not make static knowledge live commerce authority.
MCP
Tool and resource access
Connects agents to declared tools and resources under the server's own permissions and freshness boundary.
UCP
Transaction coordination
Coordinates supported commerce capabilities and transaction state such as checkout and orders.
ACP
Agentic commerce transactions
Carries supported agentic commerce transaction exchanges under its own live contract and authority boundary.
The complete minimum
This frozen root template contains only the merchant identity, official website, and one public catalog entry.
Optional next step: add one product knowledge document for a product page when every fact can cite a visible Source.
# Example Outdoor Gear
> Lightweight outdoor equipment for hikers.
SKU.md: [1.0.0-beta](https://sku.md/spec/1.0.0-beta/)
Website: [example-outdoor.com](https://www.example-outdoor.com/)
## Catalog
- [All products](https://www.example-outdoor.com/collections/all)From store URL to a checked /sku.md in five minutes
01
Generate
Enter a public storefront. Review the detected merchant name, summary, website, and one public catalog link.
02
Publish
Copy or download the Markdown, then place the exact file at the root /sku.md path on your own domain.
03
Validate
Check the published URL for the exact path, HTTP 200, allowed content type, UTF-8, safe redirects, and valid content.