diff --git a/maintenance/merge-library.php b/maintenance/merge-library.php
index 8996d2b5..1033aecd 100755
--- a/maintenance/merge-library.php
+++ b/maintenance/merge-library.php
@@ -1,6 +1,9 @@
 #!/usr/bin/php
 <?php
 
+require_once 'common.php';
+assertCli();
+
 /**
  * Compiles all of HTML Purifier's library files into one big file
  * named HTMLPurifier.standalone.php. Operates recursively, and will