diff --git a/lib/cyberarm_engine.rb b/lib/cyberarm_engine.rb
index ca80a55..bdb27c6 100644
--- a/lib/cyberarm_engine.rb
+++ b/lib/cyberarm_engine.rb
@@ -9,6 +9,7 @@ require "json"
 
 require_relative "cyberarm_engine/version"
 require_relative "cyberarm_engine/stats"
+require_relative "cyberarm_engine/result"
 
 require_relative "cyberarm_engine/common"
 
diff --git a/lib/cyberarm_engine/result.rb b/lib/cyberarm_engine/result.rb
new file mode 100644
index 0000000..bd06902
--- /dev/null
+++ b/lib/cyberarm_engine/result.rb
@@ -0,0 +1,20 @@
+module CyberarmEngine
+  # result pattern
+  class Result
+    attr_accessor :error, :data
+
+    def initialize(data: nil, error: nil)
+      @data = data
+      @error = error
+    end
+
+    def okay?
+      !@error
+    end
+
+    def error?
+      @error || @data.nil?
+    end
+  end
+end
+