diff --git a/src/cli/document/clean.php b/src/cli/document/clean.php
index a1b8cde..5ca5672 100644
--- a/src/cli/document/clean.php
+++ b/src/cli/document/clean.php
@@ -1,5 +1,8 @@
 <?php
 
+// Prevent multi-thread execution
+$semaphore = sem_get(crc32('yo.cli.document.clean'), 1);
+
 // Load dependencies
 require_once __DIR__ . '/../../../vendor/autoload.php';