How do I add menu options dynamically?

This is what I'm doing right now

code

CODE
module Test_Module
  
  COMMAND_NAME = "TEST"
  TEST_ENABLED = false
  TEST_ACCESS = false

end

class Window_MenuCommand < Window_Command
  #--------------------------------------------------------------------------
  # * Add test command to List
  #--------------------------------------------------------------------------
  alias add_main_commands_tsuki add_main_commands
  def add_main_commands
    add_main_commands_tsuki
    if Test_Module::test_ENABLED
      add_command(Test_Module::COMMAND_NAME, :test, Test_Module::TEST_ACCESS)
    end
  end
end

class Scene_Menu < Scene_MenuBase
  #--------------------------------------------------------------------------
  # * Add test handler
  #--------------------------------------------------------------------------
  alias create_command_window_tsuki create_command_window
  def create_command_window
    create_command_window_tsuki
    if Test_Module::test_ENABLED
      @command_window.set_handler(:test,    method(:command_test))
    end
  end
  
  def command_test
    SceneManager.call(Scene_test)
  end
end



The idea is so that if the constant is enabled (via scripting), the option will appear in the menu.
This adds the menu option, but if I hit reset, it is still available. Which makes sense cause the constant is now true.

Where should I be putting the variable so that it is specific to save games, and additionally, I also want to check if any save game has that variable set to a specific value as well (for out-of-game processing like during the title screen)

I'm thinking I should place it somewhere where the scope is local to an instance of the game rather than the entire game in general, but I'm not sure where to put it. I'll be adding a class that will provide methods for getting and setting the value of that variable, but I think it will still need to be a global variable.