Tencent CubeSandbox Open-Sourced: Hardware-Level AI Agent Execution Environment with 60ms Cold Start Time

In April 2026, Tencent Cloud fully open-sourced CubeSandbox under the Apache 2.0 license. Based on RustVMM and KVM MicroVM, this project provides hardware-level isolated sandboxes for AI Agents: it features cold startup time of less than 60ms, additional memory overhead of less than 5MB per instance, and natively compatible with the E2B SDK. The CubeVS component implements network isolation and outbound traffic control via eBPF. This article verifies official data and architecture, introduces acceleration principles such as resource pool pre-creation and snapshot cloning, and provides quick experience steps for the E2B SDK, which is suitable for developers paying attention to Agent infrastructure and self-hosted sandboxes.