diff --git a/home-manager/modules/emacs/config.org b/home-manager/modules/emacs/config.org
index 9dab26f..9bb964e 100644
--- a/home-manager/modules/emacs/config.org
+++ b/home-manager/modules/emacs/config.org
@@ -1425,7 +1425,7 @@ Enable and configure =auto-insert-mode= for Horus projects
 
   (when (file-executable-p my/generate-cpp-file-executable)
     (define-auto-insert
-      (rx ".[ch]pp" eos)
+      "\\.[ch]pp\\'"
       (lambda nil (call-process my/generate-cpp-file-executable nil t nil buffer-file-name))))