diff --git a/usersystem.capnp b/usersystem.capnp
index 0148425..60c2a71 100644
--- a/usersystem.capnp
+++ b/usersystem.capnp
@@ -28,6 +28,8 @@ struct UserSystem
     	getUserList @0 () -> ( user_list :List(User) );
 
         addUser @1 (username :Text, password: Text) -> User;
+        # DEPRECATED: use `addUserFallible` instead
+
     	removeUser @2 (user: User);
 
         struct AddUserError {