What I disliked about the Claude sandbox is that their IPs are blocked by many platforms, which makes webfetch etc. nearly impossible. I had to write a skill to avoid that. Best example is reddit that blocks all access for LLMs. I mean, it's surely understandable why those paltforms do it. But for your own purpose like research and can be a bit annoying.

Docker sandboxes do that. They take quite bit of resources though, almost same as a standard VM.

I need to mount directories or remove after creation easily, like I do with containers.

Gateway would be good too.

Firewall needs more functionality.