During a recent subway outage in San Francisco I decided to build a webapp in the spirit of "Do I Need an Umbrella," basically to answer the question "Should I take the subway or a bus?"

In the interest of learning new tools I decided to vibe code it as much as possible.

First, I had Claude Code write a background script to download images of the real-time circuit diagram of the subway, which are publicly available here: http://sfmunicentral.com/

Next I had it build an image labeler tool in tkinter, which turned out to need a lot of manual tweaking before I could even get to the labeling. Seemed like the right tool for the job, but it would have saved time if I'd built it from scratch myself.

The most interesting part was turning the labeled image data into predictions with pytorch. Claude wrote the initial script fairly quickly, but as these things go it required manual tweaking and second guessing myself on the images flagged as outliers. I'll admit I got embarrassingly far along before realizing that Claude hadn't enabled pytorch's GPU support; a real facepalm moment on my part.

For those curious, brave, or crazy enough to dive in the source code is available here under an MIT license: https://github.com/MrEricSir/munimet.ro