diff --git a/src/spec/Type.php b/src/spec/Type.php
index 3c622824..cea7e11c 100644
--- a/src/spec/Type.php
+++ b/src/spec/Type.php
@@ -20,4 +20,5 @@ class Type
     const STRING = 'string';
     const BOOLEAN = 'boolean';
     const OBJECT = 'object';
+    const ARRAY = 'array';
 }