Show HN: Moo, Git versions code, moo versions machines
Moo is a new macOS (Apple Silicon) tool from Ito that gives each git branch or agent attempt its own isolated Linux microVM with copy-on-write disks, enabling sub-500ms forking of large environments. It versiones machine state with the repo, so checking out an old commit and running "moo new" boots the exact runtime from that point.
Background
- **Moo** is a new open-source tool from **Ito (ito.ai)**, a company that makes a code-review platform that actually executes the code being reviewed.
- It solves a problem for developers running many AI coding agents in parallel against the same repository: collisions on databases, ports, and services that Git worktrees (which only isolate files) cannot prevent.
- Moo gives each branch or agent its own isolated Linux microVM (lightweight virtual machine). The VM's state (installed packages, running services, data) is snapshotted and tagged with the Git commit. You can check out an old commit and instantly boot the exact runtime environment that existed at that point, not just the code.
- Under the hood it uses **copy-on-write (CoW) disks** (via APFS clonefile on macOS), so forking a 20 GB environment takes under 500ms. It currently only runs on **macOS Apple Silicon** (M-series chips) due to these dependencies.
- The punny name: Git versions code ("git" → version control), Moo versions machines ("moo" → like a cow's sound → "machines").