What placement never changes

• Function names, namespaces, schemas, and the manifest format.
• The { result } / { error } envelope, at the function boundary and on every gateway call.
• Signal identity: a signal dispatched by a wasm-hosted function is indistinguishable downstream from the same signal dispatched by a docker-hosted one.
• The identity model: execution is bound independently to a world and acting principal by the host; no host puts a credential or scope key inside the unit.
• Declarative schemas remain independent of placement. Activating a declaration requires host support and the applicable Realm and resource approvals.