SA_5 Redescription Legality Under Role Preservation

This paper formalizes the conditions under which redescription is legal within an admissible system. It shows that redescription is permitted only when role preservation is maintained across anchors, tensors, and skin; any redescription that alters role assignment constitutes illicit scope transport and fails closed. The argument proceeds by exhaustion, establishing that legality is a structural property rather than a matter of convention, convenience, or interpretive freedom. The treatment is declarative and non-procedural, placing on record the necessary constraints on redescription without providing methods, heuristics, or transformation rules.