--- xtp/include/votca/xtp/eigen.h.orig	2025-10-03 18:44:55 UTC
+++ xtp/include/votca/xtp/eigen.h
@@ -21,6 +21,9 @@
 #ifndef VOTCA_XTP_EIGEN_H
 #define VOTCA_XTP_EIGEN_H
 
+// Standard includes
+#include <cassert>
+
 // CMake Generated file
 // clang-format off
 // order seems to matter here
