diff --git a/src/applications/diffusion/herald/HeraldPreCommitAdapter.php b/src/applications/diffusion/herald/HeraldPreCommitAdapter.php
--- a/src/applications/diffusion/herald/HeraldPreCommitAdapter.php
+++ b/src/applications/diffusion/herald/HeraldPreCommitAdapter.php
@@ -87,4 +87,8 @@
       $this->hookEngine->getRepository()->getProjectPHIDs());
   }
 
+  public function supportsWebhooks() {
+    return false;
+  }
+
 }
diff --git a/src/applications/herald/action/HeraldCallWebhookAction.php b/src/applications/herald/action/HeraldCallWebhookAction.php
--- a/src/applications/herald/action/HeraldCallWebhookAction.php
+++ b/src/applications/herald/action/HeraldCallWebhookAction.php
@@ -14,6 +14,10 @@
   }
 
   public function supportsObject($object) {
+    if (!$this->getAdapter()->supportsWebhooks()) {
+      return false;
+    }
+
     return true;
   }
 
diff --git a/src/applications/herald/adapter/HeraldAdapter.php b/src/applications/herald/adapter/HeraldAdapter.php
--- a/src/applications/herald/adapter/HeraldAdapter.php
+++ b/src/applications/herald/adapter/HeraldAdapter.php
@@ -1211,6 +1211,11 @@
 /* -(  Webhooks  )----------------------------------------------------------- */
 
 
+  public function supportsWebhooks() {
+    return true;
+  }
+
+
   final public function queueWebhook($webhook_phid, $rule_phid) {
     $this->webhookMap[$webhook_phid][] = $rule_phid;
     return $this;
diff --git a/src/applications/metamta/herald/PhabricatorMailOutboundMailHeraldAdapter.php b/src/applications/metamta/herald/PhabricatorMailOutboundMailHeraldAdapter.php
--- a/src/applications/metamta/herald/PhabricatorMailOutboundMailHeraldAdapter.php
+++ b/src/applications/metamta/herald/PhabricatorMailOutboundMailHeraldAdapter.php
@@ -64,4 +64,8 @@
     return pht('Mail %d', $this->getObject()->getID());
   }
 
+  public function supportsWebhooks() {
+    return false;
+  }
+
 }