As a best practice, we typically have an eSpace that contains the entities for a given application, expose them read-only for use in queries, and have specific actions to save and delete records (which typically involve data validations and set some flag indicating deletion respectively). These actions naturally live on the Action tab in Service Studio. It would be nice to be able to associate them with the entities they pertain to, so that referencing the entities would automatically reference these actions (similar to the platform default Get, Update etc. entity actions are). Note that this is not the same as this idea
(which is also great), as that's about automatic triggers.