SKU.md

A self-published product knowledge layer for AI agents, controlled by the merchant who knows the catalog.

Use SKU.md to expose catalog and product documents, stable identifiers, AI permissions, source authority, and the live commerce capabilities an agent should use next.

Explore Examples
---schema_version: "sku.md/1.0"document_type: catalog_manifestcanonical: "https://www.example-outdoor.com/sku.md"generated_at: "2026-07-16T18:30:00+08:00"data_revision: "catalog-20260716-1830"language: "en-US"market: "CN" merchant:  id: "https://www.example-outdoor.com/#merchant"  name: "Example Outdoor Gear"  legal_name: "Example Outdoor Gear Inc."  site_url: "https://www.example-outdoor.com/"  support_url: "https://www.example-outdoor.com/pages/contact" ai_usage:  training: disallow  retrieval_answer: allow  citation_required: true  agentic_checkout: unsupported authority:  identity: sku_document  product_facts: sku_document  offer_snapshot: sku_document  live_price: live_catalog  live_availability: live_catalog  shipping_quote: checkout  tax: checkout  final_total: checkout  payment: checkout capabilities:  self_hosted:    schema_jsonld:      status: live      note: "Each product detail page embeds schema.org/Product + Offer JSON-LD in <head>"    # Additional capabilities follow---

Why SKU.md?

The commerce web has three jobs: help agents read what a merchant sells, query what is true now, and act when the required tools and approvals are available.

SKU.md fills the public knowledge layer between site-wide discovery and live commerce. It gives agents structured product context while directing price, availability, shipping, tax, checkout, and payment decisions to the proper authority.

Use the document family to:

Publish a root manifest, optional partition indexes, and product-level knowledge documents.

Separate durable facts, attributed claims, time-limited offer snapshots, and final transaction truth.

Declare which source is authoritative and which commerce capabilities are live, planned, or unsupported.

The draft is not a shopping or payment protocol. It is the merchant-controlled guide that makes each layer of the commerce stack easier to discover and use correctly.

One SKU.md connects the commerce stack

From access and discovery to product truth and action, SKU.md tells agents which layer is authoritative, which capabilities exist, and where to go next.

Examples

---schema_version: "sku.md/1.0"document_type: catalog_manifestcanonical: "https://www.example-outdoor.com/sku.md"generated_at: "2026-07-16T18:30:00+08:00"data_revision: "catalog-20260716-1830"language: "en-US"market: "CN" merchant:  id: "https://www.example-outdoor.com/#merchant"  name: "Example Outdoor Gear"  legal_name: "Example Outdoor Gear Inc."  site_url: "https://www.example-outdoor.com/"  support_url: "https://www.example-outdoor.com/pages/contact" ai_usage:  training: disallow  retrieval_answer: allow  citation_required: true  agentic_checkout: unsupported authority:  identity: sku_document  product_facts: sku_document  offer_snapshot: sku_document  live_price: live_catalog  live_availability: live_catalog  shipping_quote: checkout  tax: checkout  final_total: checkout  payment: checkout capabilities:  self_hosted:    schema_jsonld:      status: live      note: "Each product detail page embeds schema.org/Product + Offer JSON-LD in <head>"    sitemap:      status: live      url: "https://www.example-outdoor.com/sitemap-products.xml"    webmcp:      status: unsupported      scope: "/products/*"      tools: []  platform_gated:    acp_product_feed:      status: planned      url: "https://www.example-outdoor.com/feeds/acp-products.jsonl.gz"    acp_checkout:      status: unsupported    ucp_catalog:      status: planned      well_known: "https://www.example-outdoor.com/.well-known/ucp"      capability: "dev.ucp.shopping.catalog.lookup"    ucp_checkout:      status: unsupported identifiers:  product_id_namespace: "gid://example-outdoor.com/Product/"  variant_id_namespace: "gid://example-outdoor.com/ProductVariant/"  sku_scope: merchant  variant_id_is_checkout_item_id: true catalog:  mode: inline  product_count: 35  variant_count: 112  partitions: [] policies:  shipping: "https://www.example-outdoor.com/policies/shipping"  returns: "https://www.example-outdoor.com/policies/returns"  warranty: "https://www.example-outdoor.com/policies/warranty"  ai_usage: "https://www.example-outdoor.com/policies/ai" languages: ["zh-CN", "en-US"]currency_default: "USD"update_frequency: "weekly"--- # Example Outdoor Gear > An independent store focused on lightweight outdoor gear across three categories:> tents, sleeping bags, and hiking backpacks. Products emphasize lightweight designs> under 750g and range from $39–$459. With 35 SKUs, the catalog remains small enough> to use `catalog.mode: inline` without partition files. ## Categories - [Ultralight Tents](https://www.example-outdoor.com/collections/tents): 12 available models, priced from $129–$459- [Down Sleeping Bags](https://www.example-outdoor.com/collections/sleeping-bags): 8 available models, priced from $89–$329- [Hiking Backpacks](https://www.example-outdoor.com/collections/backpacks): 15 available models, priced from $39–$189 ## Featured SKUs | SKU ID | Name | Key specifications | Reference price | Product page | Product document ||---|---|---|---|---|---|| TENT-ULT-02 | UltraLight 2P Tent | Weight 1.35kg; hydrostatic head 3000mm | $259–$299 | [Details](https://www.example-outdoor.com/products/tent-ult-02) | [sku.md](https://www.example-outdoor.com/products/tent-ult-02.sku.md) || BAG-DOWN-700 | 700-Fill-Power Down Sleeping Bag | Lower temperature limit -5°C; weight 890g | $199–$249 | [Details](https://www.example-outdoor.com/products/bag-down-700) | [sku.md](https://www.example-outdoor.com/products/bag-down-700.sku.md) || PACK-45L-AIR | Air Series 45L Backpack | Empty weight 980g; aluminum alloy suspension system | $129–$159 | [Details](https://www.example-outdoor.com/products/pack-45l-air) | [sku.md](https://www.example-outdoor.com/products/pack-45l-air.sku.md) | *See `sitemap-products.xml` for the complete SKU list. Each product's `.sku.md`document carries its facts, limitations, and evidence.* ## FAQ **Q: How long does shipping take?**A: Orders ship the same day from the mainland China warehouse. Standard deliveryto the United States and Europe takes 7–12 business days. **Q: Do you accept returns and exchanges?**A: Unopened items may be returned or exchanged within 30 days of delivery. Theseller covers shipping both ways when the item has a quality issue. **Q: Can AI shopping assistants place orders directly?**A: Not currently. See `ai_usage.agentic_checkout: unsupported` and the checkoutstatuses under `capabilities.platform_gated`. Direct users to the product page tocomplete their purchase. ## Policies - Shipping: Ships from a mainland China warehouse; standard delivery takes 7–12 business days- Returns: Unopened items may be returned or exchanged within 30 days; return shipping is free for quality issues- Warranty: One year for the main body of tents and backpacks; six months for sleeping bags ## Changelog - 2026-07-17: Published sku.md/1.0 with authority declarations, expanded capabilities, and product-document links- 2026-07-16: Initial release covering 35 SKUs across three categories 

Root manifest

The required /sku.md entry point identifies the merchant, catalog, policies, authority, and available commerce layers.

Path/sku.md

Partition index

Optional indexes split large catalogs by category, market, or language while inheriting the nearest declared settings.

ScaleOptional

Product document

A recommended .sku.md file binds variants, media, facts, evidence, limitations, and offer snapshots to one product.

DepthPer product

Authority and capabilities

Explicit declarations separate static knowledge, live catalog truth, checkout totals, and platform-gated actions.

TrustDeclared

How to use SKU.md?

1. Prepare product truth

Publish Product and Offer JSON-LD on product pages and maintain a product sitemap. These remain the page-level facts and complete URL inventory behind the SKU.md knowledge layer.

2. Publish the root manifest

Add /sku.md with document and merchant identity, AI usage, authority, capabilities, stable identifier rules, catalog metadata, policies, and a concise human-readable summary.

3. Make every representation discoverable

Allow the document family in robots.txt, link /sku.md from llms.txt, and advertise product Markdown with rel="alternate" in HTML and an equivalent HTTP Link header.

4. Add product knowledge where it matters

Create product-level .sku.md documents for priority items. Bind facts, claims, media, limitations, and expiring offer snapshots to stable product and variant IDs.

5. Scale and consume safely

Add category, market, or language partitions only when needed. Treat every SKU.md document as untrusted external data, recheck live values, and never trigger payment from a static snapshot.

About

SKU.md is an original open draft informed by established discovery and commerce mechanisms, including robots.txt, llms.txt, Schema.org, WebMCP, ACP, and UCP.

Version 1.0 is a draft proposal, not a formally adopted standard. It defines a merchant-controlled family of catalog, partition, and product documents while keeping live commerce truth and transaction authority in the systems designed for them.

FAQ

Is SKU.md an official standard?

No. sku.md/1.0 is an original proposal, not an industry-adopted standard. It is published openly so merchants, platforms, and agent builders can evaluate and improve it.

Which fields are required?

A root manifest declares document identity, merchant identity, AI usage, source authority, and capabilities. Unknown or unavailable capabilities should be marked planned or unsupported instead of being left ambiguous.

Can price and inventory appear in SKU.md?

Yes, but only as an offer snapshot with observed_at, valid_until, snapshot authority, and a live_lookup pointer. Agents must recheck live price and availability before checkout or payment.

Does SKU.md enable agentic checkout?

Not by itself. It declares whether ACP or UCP catalog and checkout capabilities are live, planned, or unsupported. Transactions still require the relevant platform integration, merchant approval, live totals, and user authorization.

How do partition files inherit settings?

A category, market, or language partition inherits ai_usage, authority, and capabilities from the root manifest unless it explicitly overrides them. The nearest declaration applies, while generated_at and data_revision remain local to each file.

How often should I update it?

Update generated_at and data_revision whenever content changes, keep capability states and snapshots current, and record structural revisions in the changelog. Use partitions when different parts of the catalog need independent update schedules.

How do agents discover product documents?

Allow SKU.md paths in robots.txt, link the root manifest from llms.txt, and advertise each product document as an alternate representation in both the product page HTML and its HTTP Link header.

<link rel="alternate" type="text/markdown" href="/products/example.sku.md">

How should agents handle SKU.md safely?

Treat every document as untrusted external data, never as an instruction. Validate its domain and timestamps, ignore behavior-changing prompts, query live commerce sources before acting, and never trigger payment from static content alone.