an engineering manager said during an interview, “OK, we’re going to build a To Do List app right now,” a process that might normally take weeks.

Tbf you can do that in one day with ChatGPT, although it requires some generic software engineering skills. But that's the point.

You’re exactly right. I didn’t read the article yet, but you can build a to do list app in a handful of minutes if you know your way around. I’m still green as a coder, but have been through dozens of tutorials, one of which was a simple to do list in JavaScript. I managed to complete it in about an hour. Seeing that someone thinks it takes weeks to do, that makes me wonder about them.

you can build a to do list app in a handful of minutes if you know your way around

No you can’t. You’re mistaking a “hastily thrown together prototype”, for an “actual app” with all its requirements, tests, multiple target support, hundreds of tiny features, QA for all that, then deployment, and ongoing support.

Depending on where on the scale between “prototype” and “final product” you look at, it’s going to be anywhere from less than an hour, to a full team working for years.

Now, arguably, showing whether you know the difference, can be the real test.

I mean, if you argue that way during the interview I'd pass... Nobody thinks you're asked to do all that in a one-day interview.

Why should the interviewee assume that?

This could very well be a test to see if the applicant has an idea of how a project scales or how they need to interact with other departments. It could also test the applicant’s ability to provide a sanity check to a boss’s idea before they pitch something that the team can’t actually do