diff --git a/mmv1/products/compute/ServiceAttachment.yaml b/mmv1/products/compute/ServiceAttachment.yaml
index 9b52db126f15..f913840817a1 100644
--- a/mmv1/products/compute/ServiceAttachment.yaml
+++ b/mmv1/products/compute/ServiceAttachment.yaml
@@ -193,6 +193,7 @@ properties:
       An array of projects that are allowed to connect to this service
       attachment.
     send_empty_value: true
+    is_set: true
     item_type: !ruby/object:Api::Type::NestedObject
       properties:
         - !ruby/object:Api::Type::String