diff --git a/src/modules/ad/interface/grpc-controllers/ad.proto b/src/modules/ad/interface/grpc-controllers/ad.proto
index 267d106..da93584 100644
--- a/src/modules/ad/interface/grpc-controllers/ad.proto
+++ b/src/modules/ad/interface/grpc-controllers/ad.proto
@@ -58,6 +58,7 @@ message Waypoint {
 }
 
 enum Frequency {
+  UNSPECIFIED = 0;
   PUNCTUAL = 1;
   RECURRENT = 2;
 }