Nono has been my daily driver since the start of the year. It's not a perfect sandbox -- that's for sure. For example, the default network rules let you escape via a global TMUX server. But it is extremely practical. It gives me enough guarantees to feel confident about running in YOLO mode. So far nothing has gone awry.

Why do you say that?

Eg, if used with Colima in macOS, it means I can run a devcontainer in an isolated VM and Nono inside the devcontainer can restrict a lot what can and cannot be done.

You get credentials proxying and network outbound limits.

How is Docker Sandbox better sandboxed?

As you as your Go build fails because you haven't put the local cache dir in the "allowed directories", you'll understand how painful this is, as well as most tools based on bubblewrap/sandbox-exec. There is a difference between a clean environment with standard setup vs a layer on top of everyone's existing tools/setup, especially in a enterprise environment.

(I'm sure you can spend time to come up with a proper bubblewrap configuration that allows go build to succeed, but it's probably not worth the effort.)