diff --git a/src/workflow/ArcanistGitHookPreReceiveWorkflow.php b/src/workflow/ArcanistGitHookPreReceiveWorkflow.php
--- a/src/workflow/ArcanistGitHookPreReceiveWorkflow.php
+++ b/src/workflow/ArcanistGitHookPreReceiveWorkflow.php
@@ -41,6 +41,10 @@
     return false;
   }
 
+  public function getSupportedRevisionControlSystems() {
+    return array('git');
+  }
+
   public function run() {
     $working_copy = $this->getWorkingCopy();
     if (!$working_copy->getProjectID()) {