The after-hours encounter is complete only when the regular GP knows about it. The service has a reliable process for returning responsibility to the patient's own general practice after each contact, by secure electronic message or another agreed route, conveying the presenting problem, assessment, treatment and medicines given, referrals, pending results and the follow-up expected of the practice, usually by the start of the next business day and immediately for urgent matters. Handover within the service between shifts is also structured and documented.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.