Can someone who understands web UI programming tell me if this would be good for my local agent to use to produce HTML based reports and outputs for me? Or for TUI outputs?

There was this submission two months ago: https://news.ycombinator.com/item?id=48365904 . Basically they have a TUI frontend for the same thing. And the blog post says: "Bonsai_term would feel familiar to anyone who’d ever done web development here, and it had the huge advantage of being especially amenable to AI assistance. It was actually somewhat of a mystery to us how good the models were at writing Bonsai_term code, given how relatively obscure it is [...]"

Probably not, because your agent won’t have much info about this tool in its training set.