diff --git a/doc/api/labeltool.rst b/doc/api/labeltool.rst
index 830235f..af90b9d 100644
--- a/doc/api/labeltool.rst
+++ b/doc/api/labeltool.rst
@@ -11,4 +11,5 @@ It provides the following API:
 
 .. autoclass:: LabelTool
     :members:
+    :undoc-members: