I like Scions "merging of three pieces" (harness/env, agent provider (LLM and related config), agent def (like agents in claude/opencode))

Scion OC support is not good on main, I have a (outdated) fork which vastly improves it. There are a number of OC plugins that try to add higher level orchestration as well as independent wrappers like https://kubeopencode.github.io/kubeopencode/docs/features/

It's debatable if you need multiple harness support like Scion or something more focussed like KubeOpenCode

Checked out swarm tools for a few seconds until the main pages of the docs 404'd, not a good sign when the first three menu items do that...

One cool thing about Scion, you can attach directly to the agents in the terminal or the web ui, even seeing real-time typing appear across them if you have both open (thanks tmux!). Scion also handles all the messiness of setting up a container with auth, git worktree, and tmux. I tried to get a simple version going but it became a rabbit hole of complexity and edge cases. You can run it in "workstation" mode which is all local.