diff --git a/src/lint/linter/ArcanistPhpcsLinter.php b/src/lint/linter/ArcanistPhpcsLinter.php
index 220719ed..4568269f 100644
--- a/src/lint/linter/ArcanistPhpcsLinter.php
+++ b/src/lint/linter/ArcanistPhpcsLinter.php
@@ -29,7 +29,7 @@ final class ArcanistPhpcsLinter extends ArcanistExternalLinter {
     return 'phpcs';
   }
 
-  public function getMandatoryFlags() {
+  protected function getMandatoryFlags() {
     return array('--report=xml');
   }