diff --git a/bin/rector b/bin/rector
index e27d189ba942..178545aa43ab 100755
--- a/bin/rector
+++ b/bin/rector
@@ -20,6 +20,8 @@ error_reporting(E_ALL);
 ini_set('display_errors', 'stderr');
 gc_disable();
 
+define('__RECTOR_RUNNING__', true);
+
 // Require Composer autoload.php
 $autoloadIncluder = new AutoloadIncluder();
 $autoloadIncluder->includeCwdVendorAutoloadIfExists();