Coding agent harnesses strike me as similar to blog generators. They can be as simple or as complex as you’d like. Plugins help with adoption. And if you want it’s real easy to write your own that does exactly what you want.

Isn’t practically all simple software like this?

In a reductionist view yeah but blog generators and agent harnesses sit at a different spectrum than an EHR/Excel/whatever other insanely complex edge case ridden work you can think of