diff --git a/config/initializers/tool_attributes.rb b/config/initializers/tool_attributes.rb
index 16cdde0d..b12b6139 100644
--- a/config/initializers/tool_attributes.rb
+++ b/config/initializers/tool_attributes.rb
@@ -28,6 +28,10 @@ def cast(value)
 end
 
 class ToolPercentage < ToolFloat
+  def initialize(**rest)
+    super(min: nil, max: nil, **rest)
+  end
+
   def cast(value)
     value = super(value)