Emacs makes for excellent Agent harness. With https://github.com/xenodium/agent-shell/ , this is the only UI I use for working with agents.

What makes this great is infinite hack-ability of the interface and agents have become pretty good at writing elisp packages, so basically you can have a workflow exactly how you want.

I wish I had time to make a screencast about this, but If you are a Emacs user and not using Emacs for agentic stuff, you are missing out IMO.