Index: src/applications/audit/editor/PhabricatorAuditCommentEditor.php
===================================================================
--- src/applications/audit/editor/PhabricatorAuditCommentEditor.php
+++ src/applications/audit/editor/PhabricatorAuditCommentEditor.php
@@ -8,6 +8,8 @@
   private $auditors = array();
   private $ccs = array();
 
+  private $noEmail;
+
   public function __construct(PhabricatorRepositoryCommit $commit) {
     $this->commit = $commit;
     return $this;
@@ -28,6 +30,11 @@
     return $this;
   }
 
+  public function setNoEmail($no_email) {
+    $this->noEmail = $no_email;
+    return $this;
+  }
+
   public function addComment(PhabricatorAuditComment $comment) {
 
     $commit = $this->commit;
@@ -297,7 +304,9 @@
     id(new PhabricatorSearchIndexer())
       ->indexDocumentByPHID($commit->getPHID());
 
-    $this->sendMail($comment, $other_comments, $inline_comments, $requests);
+    if (!$this->noEmail) {
+      $this->sendMail($comment, $other_comments, $inline_comments, $requests);
+    }
   }
 
 
Index: src/applications/diffusion/conduit/ConduitAPI_diffusion_createcomment_Method.php
===================================================================
--- src/applications/diffusion/conduit/ConduitAPI_diffusion_createcomment_Method.php
+++ src/applications/diffusion/conduit/ConduitAPI_diffusion_createcomment_Method.php
@@ -21,6 +21,7 @@
       'phid'    => 'required string',
       'action'  => 'optional string',
       'message' => 'required string',
+      'silent'  => 'optional bool',
     );
   }
 
@@ -73,6 +74,7 @@
 
     id(new PhabricatorAuditCommentEditor($commit))
       ->setActor($request->getUser())
+      ->setNoEmail($request->getValue('silent'))
       ->addComment($comment);
 
     return true;