Units and numerics

Why it exists

A packing answer is a decision about physical goods. If the arithmetic drifts the proof drifts with it, so the whole path is exact and mixing inches with millimetres in one request is safe.

What a useful refusal looks like

The engine returns the rule that refused, the item it refused, and the measured value against the configured threshold. It also states how strongly that is backed: proven, observed, inferred, or unknown because a search limit was reached first.