Microsoft eXecution Container (MXC): Sandboxed Execution for Untrusted Code

Repositorymicrosoft/mxcTool

Microsoft eXecution Container (MXC) is a cross-platform sandboxed code execution framework designed for running untrusted workloads such as AI model output, plugins, and tools across Windows, Linux, and macOS. It wraps native OS containment mechanisms and VMs into a unified policy engine and typed SDKs.

Key points

  1. Cross-platform containment using native backends: Windows (ProcessContainer, WSLC), Linux (Bubblewrap, LXC, MicroVM), and macOS (Seatbelt).
  2. Fine-grained, policy-driven controls covering filesystem access, network rules (proxy, outbound filtering), and UI permissions.
  3. Typed in-process SDKs available for Rust, .NET, and Node.js.
  4. Full lifecycle management for persistent containers, including provisioning, execution, stopping, and cleanup.

Why it matters

As AI agents and automated code-generation pipelines proliferate, running arbitrary code safely becomes essential. MXC simplifies this by eliminating the need to write custom platform-specific sandbox integrations, standardising security configurations via declarative JSON policies.

Analysis

MXC directly targets the security boundary required when executing LLM-generated code or untrusted extensions. Implemented primarily in Rust and distributed under the MIT licence, it embeds directly into client applications via SDKs rather than requiring standalone daemon management. The core engine appears functional, though advanced backends such as Hyperlight and MicroVMs remain explicitly experimental.

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Summary generated by AI (Gemini 3.8 Flash, 9 October 2026). It may contain errors – the original source is authoritative.

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