(i.e.

auto

would look at sys.stdout.istty() and pass that bool to the engine?)

yea. i guess it’s maybe a bit more explicit…?

And it’s not as easy to say

--no-ui

than

--ui=none

. You have to remember what the enum options are with the latter

I don't think that's a huge concern. the help text will tell you what the enum values are, and we expect this to be a rarely-touched option

imo, boolean is fine here.