Appointment Guardian: An Agentic NHS Appointment Recovery System
The letter arrived on a Tuesday. Oncology outpatient appointment, 9:15am, Thursday fortnight. It was in English. The patient spoke Somali.
She didn't attend. The clinic marked her DNA — Did Not Attend — and returned the slot to the general pool. Three weeks later, a re-booking letter arrived, also in English. By the time a care navigator reached her by phone, her chemotherapy cycle had shifted. The treatment window had narrowed.
This happens eight million times a year across the NHS. The aggregate cost is approximately £1.2 billion annually, but in oncology the cost isn't primarily financial — it's clinical. Missed chemotherapy cycles and delayed radiotherapy planning disrupt treatment pathways engineered around strict timing for efficacy. The slot that goes unfilled at 9:15am on Thursday is time that cannot be recovered by anyone on the waiting list behind her.
I built Appointment Guardian this week to close a specific gap: not sending the reminder, but handling what comes after it. The system imports appointments from FHIR, generates personalised reminders in the patient's language using a local LLM, manages patient replies, classifies barriers, routes tasks to the right care team, and escalates non-response automatically — without any human initiating each step.
It went live on a home-lab MicroK8s cluster on 2026-07-18. This post documents what I built, the four architectural decisions that shaped it, and five things that went wrong.