diff --git a/bin/cluster b/bin/cluster
index 5681801..eac0f52 100755
--- a/bin/cluster
+++ b/bin/cluster
@@ -1,5 +1,5 @@
 #!/usr/bin/env php
-<?php
+<?php declare(strict_types = 1);
 
 use Amp\ByteStream;
 use Amp\Cluster\Cluster;