I was obstinate and refused to learn docker, so I realized I can just rent a $3 VPS. If it blows up the VPS I reset it!

Then I realized the only thing I care about on my local machine is "don't touch my files", and Unix users solved that in 1970. So I just run agents as "agent" user.

I think running it on a separate machine is nicer though, because it's even simpler and safer than that. (My solution still requires careful setup and regular overhead when you get permission issues. "It's on another laptop, and my stuff isn't" has neither of those problems.)