Where it goes wrong
A hammock is sold in two lengths on one page. The structured data carries one GTIN. The specification tab lists weight once. An answer then gives the longer length and the shorter one's weight — each fact correct, the combination wrong.
What makes a variant unambiguous
- Its own GTIN, published for that variant.
- The attribute that varies, in words: "the 350 cm version".
- Facts that differ stated per variant, not once for the family.
- Where a variant has its own URL, a canonical that says which variant the
page is.
The identifier checklist is at /checklists/product-identifiers.
Why this is worth fixing first
Variant errors are invisible in a quick check: the product is named, the link is right, and the number is plausible. They surface as returns. A model cannot separate what the page does not separate — the ladder at /evidence explains why a correct citation still says nothing about the fact that was used.