← Back to Kevin's newslettersPublished: 2026 Feb 1

Hi friends,

I’m traveling the next two weeks, drop me a line if you want to grab a coffee!

LLM agent virtual machine sandbox

The other day I asked OpenAI’s Codex agent to write me a lil’ Rust program to use a bluetooth gamepad as a mouse, and I caught the agent reading files outside of the directory I started it in. I found this quite surprising, since I assumed it’d be contained within the project folder. (I was using the default settings, not the more permissive --yolo mode.)

I don’t like the idea of an LLM agent rooting around my computer and uploading anything it finds to OpenAI, so I started shopping around for a “sandbox” — something I could let an agent loose inside of while maintaining explicit control of what it sees.

I searched around and was, unfortunately, unable to find any Mac solution that met my requirements:

That’s fine — I’ve been messing with virtual machines for 20 years now, surely I can throw something together in an hour or two!

Well, uh, several busy weekends later, I’d like to present Vibe, an easy way to spin up virtual machines on ARM-based Macs.

I’m quite pleased with how it turned out:

Being able to run LLM agents as root with --yolo mode is a great experience. It feels much more like managing an IC — you provide the necessary context in a big prompt, tell them to install whatever tools they need, and then let them cook for while you go focus on something else.

While the vibe defaults are geared towards use as an LLM agent sandbox, you can customize everything with scripts and command line flags so you can use it for all sorts of other virtual machine purposes.

Check it out and let me know what you think!

Misc. stuff