I’ve accomplished quite a bit in the past couple of weeks, let’s look at where we stand with the OpenCdsi project.

If you’ve been following along at home, you’ll notice that I’ve been using Claude, an AI product of Anthropic. My first foray into serious vibe codding was the VaxEngine. After I’d exhasted my session limits a bunch of times, I decided to buy a Pro subscription. I reasoned that I’d spent hundreds of dollars on other hobbies, why should this one be different? It paid off.

VaxEngine

The original vision for WorldVax was to provide vaccine decision support to off-grid clinics. That required some sort of engine to take an immunization history and produce vaccine forecasts. I never got it right.

VaxEngine is the core of the WorldVax vision. It isn’t perfect but it has an 84% pass rate on the conformance test corpus.

The core of the VaxEngine is available as a nuget package from Github.

Clinical Reference

The CDC Pink Book is packaged as a .NET library to provide narrative text explaining the engines decisions.

The ClinicalReference library is available as a nuget package from Github.

API

The VaxEngine is exposed as an RPC-ish API. In addition, the CDSi Supporting Data is available as resource-style endpoints.

The API is available as a Docker images from Github.

Mobile App

The mobile app is built with the .NET MAUI cross-platform framework. It is running on Android 16 and Windows 11. The app runs the VaxEngine locally, supporting the off-grid vision of WorldVax. It contains both the engine and the clinical reference along with a simple patient database.

The app is available on Github.

Final Thoughts

It’s been an exciting few weeks for me as I built all of this with Claude. If I’d been more rational, I might have checked r/claudecode to learn about things like prompt engineering or RAG or GAN. But that’s not really my way, is it? Jump in and learn to swim. Throw yourself at the ground until you miss.

Those of you who have been doing this for a while might smirk and say “Look at the noob! How precious!” Well, I think I understand.

I have seen the light.

September 12, 2026