diff --git a/ufo/automator/app_apis/basic.py b/ufo/automator/app_apis/basic.py
index f9fc1e00d..8522b4244 100644
--- a/ufo/automator/app_apis/basic.py
+++ b/ufo/automator/app_apis/basic.py
@@ -129,7 +129,7 @@ def close(self) -> None:
             pass
 
     @property
-    def type_name(self):
+    def type_name(self) -> str:
         return "COM"
 
     @property