The memory forking is really interesting. I wonder if copy-on-write at the VM level, O(1) with respect to machine size, won't scale cost with how many forks to take, but 320ms median seems good for the branch-and-explore pattern without reprovisioning every time.

One gap I'm noticing in these comments and in the current sandbox landscape is Windows. Every platform mentioned in these comments like E2B, Daytona, Fly Sprites, Sandflare appears Linux-native. Makes sense for coding agents targeting Debian environments, but a real category exists to automate Windows-specific workflows: enterprise software, ERP systems, anything that runs only on Windows.

If anyone wants to run agents in Mac or Linux and need to access Windows for computer use, Dexbox could be helpful. [github.com/getdexbox/dexbox]

I launched an open source developer tool called Dexbox to run agent workloads that quickly provision and run Windows desktops. It's a CLI and MCP experience that's different from Freestyle, but slightly closer to our Windows-specific production infra, Nen. I like Freestyle's cool UI that shows off the unique technical approach and developer friendliness. Nen's a bit closer to that experience.