I OCR'd the text with Google Lens, described who had what, and after a bit of prompt engineering (e.g., adding "Be sure to get your math correct" to make the AI's arithmetic check out, and convincing the AI to split shared items evenly), it totally worked: https://gist.github.com/spinda/967322dda1c04d9864f3efd45addc...
Then I started experimenting with describing a hypothetical check-splitting app to the AI, and asking it to feed me JSON commands to update the UI in response to messages from me telling it what the user was doing. The results were promising! And then the similarity to the Redux data loop jumped out, and I built this generic plugin to wire ChatGPT up to apps for real.