diff --git a/lib/model-helper.js b/lib/model-helper.js
index 1a23f23..7ac4688 100644
--- a/lib/model-helper.js
+++ b/lib/model-helper.js
@@ -232,8 +232,13 @@ var modelHelper = module.exports = {
       'format',
       'defaultValue',
       'enum',
+      'items',
       'minimum',
+      'minItems',
+      'minLength',
       'maximum',
+      'maxItems',
+      'maxLength',
       'uniqueItems',
       // loopback-explorer extensions
       'length',