Tencent Cloud has open-sourced its AI Agent sandbox, CubeSandbox, under the Apache 2.0 license. Written in Rust, CubeSandbox provides an isolated environment for running agent-generated code, preventing unauthorized access and accidental file deletions. It supports the E2B interface, allowing seamless transition from E2B's hosted service to a self-deployed Cube instance by modifying an environment variable. CubeSandbox boasts impressive performance metrics, with a single-concurrency cold start time under 60ms and the ability to run over 2,000 sandboxes simultaneously on a 96-core server. This is achieved through innovations like resource pool pre-allocation and Rust reimplementation, significantly reducing memory usage and startup times compared to Docker containers and traditional virtual machines. CubeSandbox has already processed tens of billions of requests within Tencent Cloud's infrastructure, and external clients like MiniMax have utilized it for large-scale AI training scenarios.