document
Checks one supplied Markdown document for required structure, safe links, size, and source rules.
Normative English specification
The small, source-backed SKU.md contract.
Version 1 defines two pure-Markdown documents: a root catalog and an optional product knowledge document. Fixed machine labels stay in English; human content may use any language.
Root catalog
Publish exactly at /sku.md. It identifies the merchant, official website, and at least one same-origin public catalog link.
# 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)Product knowledge
Use one document per canonical product page. Every fact or optional knowledge item ends with one or more absolute HTTPS Source links.
# UltraLight 2P Tent> A lightweight two-person tent for three-season backpacking. SKU.md: [1.0.0-beta](https://sku.md/spec/1.0.0-beta/)Catalog: [Example Outdoor Gear](https://www.example-outdoor.com/sku.md)Product: [Official product page](https://www.example-outdoor.com/products/tent)Updated: 2026-08-11 ## Facts- Packaged weight is 1.35 kg. [Source](https://www.example-outdoor.com/products/tent)Product HTML alternate
A product page may declare its Markdown alternate, while the root /sku.md and Product knowledge links remain the primary discovery path.
<link rel="alternate" type="text/markdown" href="https://www.example-outdoor.com/products/tent.sku.md">Syntax
Use headings, fixed label lines, lists, and ordinary Markdown links. Unknown sections remain human-readable but are not normative fields.
Three validation scopes
A result is only meaningful when its scope is clear.
published
Adds exact URL, HTTP 200, MIME, UTF-8, redirect, and final-resource checks.
graph
Adds root/product backlinks, same-origin relationships, reachable sources, and duplicate or cycle checks.
Reference Consumer behavior
A conforming consumer keeps source links with factual answers and does not turn a static document into live commerce authority.
- Cite the Source used for each product fact.
- Keep facts, guidance, limitations, and compatibility distinct.
- For current price, stock, delivery, or checkout, use a live source or say the answer is unknown.
Safety boundary
SKU.md is ordinary public Markdown, not a hidden instruction channel.
- Reject raw HTML, scripts, forms, unsafe URL protocols, oversized files, and invalid UTF-8.
- Do not claim automatic extraction is merchant-confirmed unless a person actually reviewed it.
- Do not add ranking manipulation, hidden agent instructions, or transaction credentials.
Version history
1.0.0-beta is a clean break from v0.10. There is no compatibility mode, converter, or version selector.