diff --git a/.mypy.ini b/.mypy.ini
index c0d7700dc9..bc5670dbe7 100644
--- a/.mypy.ini
+++ b/.mypy.ini
@@ -50,6 +50,8 @@ strict_optional = True
 strict_optional = True
 [mypy-aqt.taglimit]
 strict_optional = True
+[mypy-aqt.deckdescription]
+strict_optional = True
 [mypy-aqt.deckbrowser]
 strict_optional = True
 [mypy-anki.scheduler.base]
diff --git a/qt/aqt/deckdescription.py b/qt/aqt/deckdescription.py
index 01b41eaaf1..261f52ea29 100644
--- a/qt/aqt/deckdescription.py
+++ b/qt/aqt/deckdescription.py
@@ -60,6 +60,7 @@ def _setup_ui(self) -> None:
 
         button_box = QDialogButtonBox()
         ok = button_box.addButton(QDialogButtonBox.StandardButton.Ok)
+        assert ok is not None
         qconnect(ok.clicked, self.save_and_accept)
         box.addWidget(button_box)