diff --git a/resources/primitive.rb b/resources/primitive.rb
index 2abe43e..2e74992 100644
--- a/resources/primitive.rb
+++ b/resources/primitive.rb
@@ -23,6 +23,6 @@ default_action :create
 
 attribute :name, :kind_of => String, :name_attribute => true
 attribute :agent, :kind_of => String
-attribute :params, :default => Hash, :default => {}
+attribute :params, :kind_of => Hash, :default => {}
 attribute :meta, :kind_of => Hash, :default => {}
 attribute :op, :kind_of => Hash, :default => {}