Commands and OnUpdate

Is there recommended way how to have commands from plugin to be enabled or disabled. For example
when I load pulgin and add commands it have to menu or toolbar of host application is there way to have onUpdate which will enable or disable that item like it is with TAction.  We have TForm in plugIn and commands state (enabled/disabled) should correlate to choices that user  made upon that form.

You'd need to add a custom interface that would communicate this enabled/disabled state from the plugin to the host app. There is no standard interface for this provided.