"Real money, not shiny payout": a courier had Muse build a gig-driver profit calculator — then tested it like an engineer

I work in courier logistics and gave Muse a detailed problem statement: turn delivery payout, distance, time, and expense assumptions into a single-file mobile tool. Muse created the HTML/CSS/JavaScript implementation and an accompanying set of logic tests. I then downloaded the generated index.html and independently opened it in a browser, tested all three offers, checked zero-minute validation, inspected the locale switch, and published it here.

Evidence, not hype:

- Muse reported 49/49 internal logic assertions passing (self-reported).
- Independent live-page browser tests matched the expected A/B/C net and hourly results above.
- A zero-minute input is rejected instead of dividing by zero.
- The Canada button switches currency/distance labels and its per-km default without a fabricated exchange rate.
- Public HTML is a standalone file (~30 KB): no backend, account, cookies, analytics, or external JS/CSS required for calculator operation.
- Your entered offers stay in your own browser; this site does not upload them.