diff --git a/crates/wip-host/src/lib.rs b/crates/wip-host/src/lib.rs
index c049dcb..935e8ce 100644
--- a/crates/wip-host/src/lib.rs
+++ b/crates/wip-host/src/lib.rs
@@ -160,7 +160,9 @@ impl InterfaceRegistry {
     ///
     /// `validator` should be present when the host intends the reference to
     /// represent a versioned descriptor. Its presence makes the same value a
-    /// mandatory precondition for dispatch.
+    /// mandatory precondition for dispatch. Registration finalizes the
+    /// descriptor's protocol `name` to the assigned opaque reference so it
+    /// corresponds directly to [`Object::interfaces`].
     pub fn register<D>(
         &mut self,
         _definition: D,
@@ -174,7 +176,7 @@ impl InterfaceRegistry {
             return Err(RegistrationError::AlreadyRegistered);
         }
 
-        let descriptor = D::descriptor();
+        let mut descriptor = D::descriptor();
         descriptor
             .validate()
             .map_err(RegistrationError::InvalidDescriptor)?;
@@ -183,6 +185,11 @@ impl InterfaceRegistry {
             "wip-interface:{}:{}",
             self.namespace, self.next_reference
         ));
+        // The protocol model currently carries the interface identifier in the
+        // descriptor's `name` field. Finalize that identity to the same opaque
+        // reference placed on published objects; the generated Rust trait name
+        // is registration-local metadata, not wire identity.
+        descriptor.name = reference.0.clone();
         self.next_reference = self
             .next_reference
             .checked_add(1)
diff --git a/crates/wip-host/tests/host.rs b/crates/wip-host/tests/host.rs
index 2106b46..49439c7 100644
--- a/crates/wip-host/tests/host.rs
+++ b/crates/wip-host/tests/host.rs
@@ -165,7 +165,7 @@ fn registry_exposes_opaque_validated_descriptor_observations() {
     assert_ne!(reader.reference().as_str(), "Reader");
     let observation = registry.observe(reader.reference()).unwrap();
     assert_eq!(observation.reference, *reader.reference());
-    assert_eq!(observation.descriptor.name, "Reader");
+    assert_eq!(observation.descriptor.name, reader.reference().as_str());
     assert_eq!(observation.validator, None);
     observation.descriptor.validate().unwrap();
 
@@ -197,6 +197,15 @@ fn publication_is_explicit_ordered_qualified_and_request_scoped() {
             reader.reference().as_str().to_owned()
         ]
     );
+    wip_protocol::InterfaceObservation {
+        object: object.clone(),
+        descriptors: vec![
+            registry.observe(writer.reference()).unwrap().descriptor,
+            registry.observe(reader.reference()).unwrap().descriptor,
+        ],
+    }
+    .validate()
+    .unwrap();
     assert!(!format!("{object:?}").contains("private/backend/path"));
 
     let writer_result = publication