diff --git a/lib/twine/formatters/abstract.rb b/lib/twine/formatters/abstract.rb
index 64e721d..64615ef 100644
--- a/lib/twine/formatters/abstract.rb
+++ b/lib/twine/formatters/abstract.rb
@@ -3,8 +3,8 @@ require 'fileutils'
 module Twine
   module Formatters
     class Abstract
-      attr_accessor :strings
-      attr_accessor :options
+      attr_reader :strings
+      attr_reader :options
 
       def self.can_handle_directory?(path)
         return false