CubeSandbox gives every AI agent its own hardware-isolated MicroVM with a dedicated Linux kernel — not a shared-kernel container but a true KVM virtual machine — booting in under 60ms with less than 5MB of memory overhead per instance, enabling thousands of concurrent sandboxes on a single server via kernel sharing and Copy-on-Write memory. The Rust-built CubeProxy exposes an E2B SDK-compatible REST API on Axum, so existing E2B Cloud applications switch by changing one environment variable with zero client code changes. CubeMaster orchestrates cluster-level scheduling in Go while Cubelet manages node-local sandbox lifecycles including create, run, pause, resume, snapshot, and destroy operations. CubeVS, the eBPF-powered network layer, enforces per-sandbox isolation with LPM trie-based egress policies entirely in kernel space — no userspace context switches — while CubeEgress provides an L7 security proxy with per-domain, per-path, and per-method allowlists plus automatic credential injection that keeps secrets invisible to sandbox code. Hundred-millisecond-granularity snapshots enable checkpoint, rollback, and parallel fork from any saved state. The volume framework supports E2B-compatible pluggable storage with independent lifecycle and cross-sandbox sharing. Production deployment uses Terraform on Tencent Cloud or Helm charts on Kubernetes, K3s, or TKE, with full ARM64 support alongside x86_64 and AutoPause/AutoResume for cost optimization. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. Apache 2.0 licensed.