It is an asynchronous Python API for launching, controlling, snapshotting, and restoring QEMU virtual machines, with agent sandboxing as its stated use case.
The package supports x86_64 and ARM64 on macOS, Linux, and Windows. Its documentation says sandboxes can run without root privileges or Docker when the QEMU and image extras are installed. Prebuilt images include Ubuntu 24.04 and Alpine 3.23, plus desktop, agent, and computer-use variants. The package is MIT licensed.
Quicksand exposes command execution, host-directory mounts, TCP port forwarding, multiple Linux users, saved VM states, checkpoints, rollback, and optional desktop input and screenshots. Networking is isolated by default; full internet access is an explicit mode. The source does not establish security guarantees, performance against alternative sandbox runtimes, production readiness, or which Microsoft products use the library.