Role dates and validity
A person’s recorded employment start/end dates can describe that role’s history at the source’s precision. They are distinct from a capture, observation or verification timestamp. Generic relationship valid_from / valid_to fields are not part of this public contract. A database history field or page modification date must not become a customer-visible validity claim.Date semantics
The descriptive evidence JSON uses published_at, captured_at, observed_at and verified_at for the same meanings. Every field does not have every date. Date-only evidence stays in its source note; never invent a timestamp.