This is awesome - the snapshotting especially is critical for long running agents. Since we run agents in a durable execution harness (similar to Temporal / DBOS) we needed a sandboxing approach that would snapshot the state after every execution in order to be able to restore and replay on any failure.

We ended up creating localsandbox [0] with that in mind by using AgentFS for filesystem snapshotting, but our solution is meant for a different use case than Freestyle - simpler FS + code execution for agents all done locally. Since we're not running a full OS it's much less capable but also simpler for lots of use cases where we want the agent execution to happen locally.

The ability to fork is really interesting - the main use case I could imagine is for conversations that the user forks or parallel sub-agents. Have you seen other use cases?

[0] https://github.com/coplane/localsandbox

Deterministic testing of edge cases. It can be really hard to recreate weird edge cases of running services, but if you can create them we can snapshot them exactly as they are.