davila7/sandbox-runtime ? reverse-engineered prompt

Build me a lightweight sandbox runtime called srt that can wrap any command and run it with restricted filesystem and network access, without needing a full container. I want it to work as both a CLI and a library, with a simple config file that lets me allow or deny specific folders, files, domains, and local sockets. By default it should be locked down, so commands can only access what I explicitly allow, and it should clearly block anything else with useful error messages.

It should support macOS, Linux, and Windows in the way the README describes, and it should be able to sandbox things like bash commands, local MCP servers, and other arbitrary processes. Please also include debug logging, settings loading, and a way to watch for sandbox violations when the platform supports it. Keep the public API simple, make the CLI easy to use, and add tests for the core sandbox rules and command wrapping. If you need to check platform docs or current behavior for the sandbox features, look them up online.