+++ b/src/lint/engine/ArcanistConfigurationDrivenLintEngine.php
@@ -35,6 +35,7 @@ final class ArcanistConfigurationDrivenLintEngine extends ArcanistLintEngine {
PhutilTypeSpec::checkMap(
$config,
array(
+ '_comment' => 'optional string | list<string>',
'exclude' => 'optional regex | list<regex>',
'linters' => 'map<string, map<string, wild>>',
));