Completely agree. Ideally these agents would work as very smart proxy servers, so they can work for everybody in a household without futzing around with browser

Completely agree. Ideally these agents would work as very smart proxy servers, so they can work for everybody in a household without futzing around with browser-specific extensions. And such agents must to be completely outside Twitter's control; i.e. they have to be based on scraping, not some API that can be yanked at any time.