Index: auto_nodetitle.module
===================================================================
--- auto_nodetitle.module
+++ auto_nodetitle.module
@@ -37,6 +37,7 @@
     else if (auto_nodetitle_get_setting($form['#node']->type) == AUTO_NODETITLE_OPTIONAL) {
       // we will make the title optional
       $form['title']['#required'] = FALSE;
+      $form['title']['#description'] = t('Will be generated automatically if left empty.');
       $form['#submit'][] = 'auto_nodetitle_node_form_submit';
     }
   }