diff --git a/google/pubsub/v1/pubsub.proto b/google/pubsub/v1/pubsub.proto
index a0179774ff..08f9f96299 100644
--- a/google/pubsub/v1/pubsub.proto
+++ b/google/pubsub/v1/pubsub.proto
@@ -135,6 +135,7 @@ service Publisher {
   }
 }
 
+// A policy constraining the storage of messages published to the topic.
 message MessageStoragePolicy {
   // A list of IDs of GCP regions where messages that are published to the topic
   // may be persisted in storage. Messages published by publishers running in