diff --git a/neuralnetworks/1.0/vts/functional/ValidateModel.cpp b/neuralnetworks/1.0/vts/functional/ValidateModel.cpp
index cc15263..79d8594 100644
--- a/neuralnetworks/1.0/vts/functional/ValidateModel.cpp
+++ b/neuralnetworks/1.0/vts/functional/ValidateModel.cpp
@@ -24,6 +24,8 @@
 
 using implementation::PreparedModelCallback;
 
+using PrepareModelMutation = std::function<void(Model*)>;
+
 ///////////////////////// UTILITY FUNCTIONS /////////////////////////
 
 static void validateGetSupportedOperations(const sp<IDevice>& device, const std::string& message,
@@ -54,12 +56,13 @@
 }
 
 // Primary validation function. This function will take a valid model, apply a
-// mutation to it to invalidate the model, then pass it to interface calls that
-// use the model. Note that the model here is passed by value, and any mutation
-// to the model does not leave this function.
-static void validate(const sp<IDevice>& device, const std::string& message, Model model,
-                     const std::function<void(Model*)>& mutation) {
-    mutation(&model);
+// mutation to invalidate the model, then pass these to supportedOperations and
+// prepareModel.
+static void validate(const sp<IDevice>& device, const std::string& message,
+                     const Model& originalModel, const PrepareModelMutation& mutate) {
+    Model model = originalModel;
+    mutate(&model);
+
     validateGetSupportedOperations(device, message, model);
     validatePrepareModel(device, message, model);
 }
diff --git a/neuralnetworks/1.0/vts/functional/ValidateRequest.cpp b/neuralnetworks/1.0/vts/functional/ValidateRequest.cpp
index 05eefd1..0baa85b 100644
--- a/neuralnetworks/1.0/vts/functional/ValidateRequest.cpp
+++ b/neuralnetworks/1.0/vts/functional/ValidateRequest.cpp
@@ -24,15 +24,17 @@
 
 using implementation::ExecutionCallback;
 
+using ExecutionMutation = std::function<void(Request*)>;
+
 ///////////////////////// UTILITY FUNCTIONS /////////////////////////
 
 // Primary validation function. This function will take a valid request, apply a
 // mutation to it to invalidate the request, then pass it to interface calls
-// that use the request. Note that the request here is passed by value, and any
-// mutation to the request does not leave this function.
+// that use the request.
 static void validate(const sp<IPreparedModel>& preparedModel, const std::string& message,
-                     Request request, const std::function<void(Request*)>& mutation) {
-    mutation(&request);
+                     const Request& originalRequest, const ExecutionMutation& mutate) {
+    Request request = originalRequest;
+    mutate(&request);
     SCOPED_TRACE(message + " [execute]");
 
     sp<ExecutionCallback> executionCallback = new ExecutionCallback();