alt Hacker NewsOP here.
I'm confused how you see this article as a complaint about Pi. I only mention Pi at the very end to say it's one of the agents I've tried. I checked it out, found it too barebones for me and moved on, but I understand why some people prefer it. The existence of Pi isn't a counterargument to, "Why don't agents support development workflows that should be commonplace?"
The point is that pi ticks several of your wishes (e.g. knowing its own capabilities without searching the web). And it's easy to extend. I don't know Typescript, but I just ask Pi to extend itself with feature X, and it does it.