Reverse Engineering Claude Code: 10GB Ubuntu ARM64 VM and vsock RPC

foxtrot_north · reddit · 2026-07-06

A developer deconstructed the 10GB VM image within the Claude Code application's support folder, discovering that it eschews containers or Seatbelt sandboxing. Instead, it utilizes Apple's Virtualization.framework to boot a complete Ubuntu ARM64 cloud image. The control plane is managed by the daemon coworkd (internally sdk-daemon), which communicates with the host via vsock RPC and runs with root privileges; outbound network traffic is handled through a gVisor user-space network stack. The disk architecture employs a compressed golden image paired with a disposable, per-session overlay layer that automatically resets upon each boot to ensure isolation. The author has published a comprehensive technical analysis on Substack.

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