diff --git a/proto/sharing_enums.proto b/proto/sharing_enums.proto
index ab631166..e5802e7f 100644
--- a/proto/sharing_enums.proto
+++ b/proto/sharing_enums.proto
@@ -631,3 +631,13 @@ enum DesktopNotification {
 // LINT.ThenChange(
 //   //depot/google3/location/nearby/cpp/sharing/clients/dart/platform/lib/types/models.dart
 // )
+
+enum TransferUIEvent {
+  TRANSFER_UI_EVENT_UNKNOWN = 0;
+
+  // Receive attachments.
+  TRANSFER_UI_EVENT_RECEIVE_ACCEPT = 1;
+  TRANSFER_UI_EVENT_RECEIVE_PROGRESS = 2;
+  TRANSFER_UI_EVENT_RECEIVE_RECEIVED = 3;
+  TRANSFER_UI_EVENT_RECEIVE_ERROR = 4;
+}