diff --git a/ext/source_history/main.php b/ext/source_history/main.php
index f9726b4d..db98272e 100644
--- a/ext/source_history/main.php
+++ b/ext/source_history/main.php
@@ -51,6 +51,11 @@ class SourceHistory extends Extension
         }
     }
 
+    public function onRobotsBuilding(RobotsBuildingEvent $event)
+    {
+        $event->add_disallow("source_history");
+    }
+
     public function onImageAdminBlockBuilding(ImageAdminBlockBuildingEvent $event)
     {
         $event->add_part("
diff --git a/ext/tag_history/main.php b/ext/tag_history/main.php
index 4a6064be..8b9d2a79 100644
--- a/ext/tag_history/main.php
+++ b/ext/tag_history/main.php
@@ -51,6 +51,11 @@ class TagHistory extends Extension
         }
     }
 
+    public function onRobotsBuilding(RobotsBuildingEvent $event)
+    {
+        $event->add_disallow("tag_history");
+    }
+
     public function onImageAdminBlockBuilding(ImageAdminBlockBuildingEvent $event)
     {
         $event->add_part("