I built FHIR R4 support into a local-first desktop AI assistant. Here is what I learned.

Healthcare software has a problem that most AI tooling ignores completely. The data cannot leave the building.

Not "should not." Cannot. A hospital that ships patient records to a third party API is not making a tradeoff between convenience and privacy. It is breaking the law in most jurisdictions, and it is breaking the trust of every person whose record is in that system.

I build NeonCore, a Windows desktop AI assistant that parses documents entirely on the machine it runs on. No cloud upload, no data retention. A few months ago I started getting the same question from people in the health sector: can it read our patient records?

The honest answer was no. So I built it.

Why FHIR and not something simpler