diff --git a/google/chromeos/moblab/v1beta1/build_service.proto b/google/chromeos/moblab/v1beta1/build_service.proto
index cf4cb70d..a39a3989 100644
--- a/google/chromeos/moblab/v1beta1/build_service.proto
+++ b/google/chromeos/moblab/v1beta1/build_service.proto
@@ -34,6 +34,8 @@ option optimize_for = SPEED;
 // Manages Chrome OS build services.
 service BuildService {
   option (google.api.default_host) = "chromeosmoblab.googleapis.com";
+  option (google.api.oauth_scopes) =
+      "https://www.googleapis.com/auth/moblabapi";
 
   // Lists all builds for the given build target and model in descending order
   // for the milestones and build versions.