diff --git a/src/applications/conduit/method/differential/ConduitAPI_differential_close_Method.php b/src/applications/conduit/method/differential/ConduitAPI_differential_close_Method.php
index 688f5b5f4c..f7bbe40d5f 100644
--- a/src/applications/conduit/method/differential/ConduitAPI_differential_close_Method.php
+++ b/src/applications/conduit/method/differential/ConduitAPI_differential_close_Method.php
@@ -1,61 +1,66 @@
 <?php
 
 /**
  * @group conduit
  */
 final class ConduitAPI_differential_close_Method
   extends ConduitAPIMethod {
 
   public function getMethodDescription() {
     return "Close a Differential revision.";
   }
 
   public function defineParamTypes() {
     return array(
       'revisionID' => 'required int',
     );
   }
 
   public function defineReturnType() {
     return 'void';
   }
 
   public function defineErrorTypes() {
     return array(
       'ERR_NOT_FOUND' => 'Revision was not found.',
     );
   }
 
   protected function execute(ConduitAPIRequest $request) {
     $id = $request->getValue('revisionID');
 
     $revision = id(new DifferentialRevision())->load($id);
     if (!$revision) {
       throw new ConduitException('ERR_NOT_FOUND');
     }
 
     if ($revision->getStatus() == ArcanistDifferentialRevisionStatus::CLOSED) {
       // This can occur if someone runs 'close-revision' and hits a race, or
       // they have a remote hook installed but don't have the
       // 'remote_hook_installed' flag set, or similar. In any case, just treat
       // it as a no-op rather than adding another "X closed this revision"
       // message to the revision comments.
       return;
     }
 
     $revision->loadRelationships();
 
+    $content_source = PhabricatorContentSource::newForSource(
+      PhabricatorContentSource::SOURCE_CONDUIT,
+      array());
+
     $editor = new DifferentialCommentEditor(
       $revision,
       DifferentialAction::ACTION_CLOSE);
+    $editor->setContentSource($content_source);
     $editor->setActor($request->getUser());
     $editor->save();
 
     $revision->setStatus(ArcanistDifferentialRevisionStatus::CLOSED);
     $revision->setDateCommitted(time());
     $revision->save();
 
     return;
   }
 
 }