ADR-0087 exemption (no-migration-prescription): Nothing authorable is renamed, retired or re-typed: `packages/spec` is untouched, no metadata key changes its name, type or optionality, and no stored `sys_metadata` shape moves — every request body and every authored file parses byte-identically to before, so `objectstack migrate meta`, `spec-changes.json` and the generated upgrade guide have nothing to rewrite. What narrows is a TypeScript parameter annotation on one exported interface, so the affected party is a source-code implementor and the delivery channel is the compiler at their own call site. The FROM/TO block in this body is a prescription for THAT reader, not for a metadata upgrader.