I think it would be a great idea to create 'Light Agents' An agent that can view and manipulate tickets, but has no customer contact. This allows for developers and QA staff to make notes attached to tickets with all the nitty-gritty details or internal bug tracking (i.e JIRA) so that support can see it, but not the customers. The support can then tweak the wording, to be more customer friendly and send a response back to the customer.
Light agents - Ötlettár / Feature Request - Deskpro Support
Alex, could you control this with permissions out of the box, today?