Pure and separately tested, because this is where the correctness of every draft is decided. Nothing downstream can distinguish an observed detail from an invented one — the description arrives as prose either way — so the instruction is the only place that distinction can be enforced, and the tests assert it is actually present.
On a one-of-a-kind item an invented "1930s hand-thrown stoneware" is not a cosmetic error but a false claim on a public shop, and the shop answers for it rather than the model. Visible damage is called out for the same reason in reverse: a buyer finding a chip on arrival is worse than reading about it beforehand.
Categories and tags are listed rather than described, so the model chooses from what exists instead of inventing a taxonomy the storefront filters know nothing about, and declining is explicitly allowed so a model with no matching option does not pick the closest wrong one.
The note is quoted and labelled as the sender's rather than merged into the instruction: it is untrusted text from an unauthenticated stranger and should read as evidence to weigh, not as something the shop asserts. A whitespace-only note counts as no note.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
