diff --git a/masque/builder/tools.py b/masque/builder/tools.py
index 6bd7547..4162be3 100644
--- a/masque/builder/tools.py
+++ b/masque/builder/tools.py
@@ -590,6 +590,13 @@ class AutoTool(Tool, metaclass=ABCMeta):
             ) -> tuple[Port, LData]:
 
         success = False
+
+        # Initialize these to avoid UnboundLocalError in the error message
+        bend_dxy, bend_angle = numpy.zeros(2), pi
+        itrans_dxy = numpy.zeros(2)
+        otrans_dxy = numpy.zeros(2)
+        btrans_dxy = numpy.zeros(2)
+
         for straight in self.straights:
             for bend in self.bends:
                 bend_dxy, bend_angle = self._bend2dxy(bend, ccw)