diff --git a/src/applications/herald/action/HeraldAction.php b/src/applications/herald/action/HeraldAction.php
--- a/src/applications/herald/action/HeraldAction.php
+++ b/src/applications/herald/action/HeraldAction.php
@@ -23,6 +23,8 @@
   abstract public function supportsRuleType($rule_type);
   abstract public function applyEffect($object, HeraldEffect $effect);
 
+  abstract public function renderActionDescription($value);
+
   protected function renderActionEffectDescription($type, $data) {
     return null;
   }