New to this? Read it in simple words
  • Microsoft’s sandbox for AI agents is now ready for everyone.
  • It keeps an agent away from files and actions it may not use.
  • It runs on Windows 11, macOS and Linux, and it is free and open source.
  • Some controls for companies are still “coming soon”.
Words to know
Sandbox
A closed space where a program runs without reaching the rest of the computer.
Generally available
Finished and supported for everyone, no longer a test version.
Open source
Software whose code anyone may read, use and change, under a licence.

A sandbox is a closed space where a program can run without reaching the rest of the computer. Microsoft first showed its sandbox for AI agents, Microsoft Execution Containers (MXC), at its Build conference in June.

What is new

On October 7, Microsoft said MXC is now generally available. The same day, it published version 1.0.0 of the MXC kit on GitHub, the first stable release after four preview versions.

The kit has stable interfaces for Rust, .NET and Node.js. From now on, Microsoft says, version 1 updates should not break code built on it. MXC is open source under the MIT licence.

Developers write a policy that says which files and actions an agent may use. MXC can block anything else, only log it, or let it through while they test.

Sources12345

Stack
The kinds of MXC container, and where they run.

From Microsoft’s announcement of October 7; the virtual-machine container is still experimental, and some company controls are not out yet.

Where it runs

The simplest container runs on Windows 11, macOS and Linux. Stronger containers for whole sessions and for Linux on Windows work only on Windows 11. A container built as a small virtual machine is still experimental.

Microsoft says GitHub Copilot, OpenAI’s Codex, OpenClaw, Replit and LM Studio already use MXC. It lists Anthropic’s Claude Code, Perplexity and Manus among the agents that will follow. These are Microsoft’s own claims.

Sources135

Still to come

Some controls for companies are listed only as “coming soon”, with no date. They include managing containers with Intune and tracking agents’ activity with Entra identities.

The Stack says Microsoft first teased MXC in April, but Microsoft’s own Build post and the first preview kit are both dated June 2.

Sources135

Sources

Every fact in this story comes from the sources below. Open them to check our work.

  1. 1
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    Primary source · October 7, 2026MXC SDK v1.0.0 GitHub (Microsoft)
  3. 3
    Research · October 9, 2026Microsoft takes MXC, its agent management layer, GA The Stack
  4. 4
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How we checked this story

Which agents use MXC, and which will, is Microsoft’s own list. Silicon AI News is written with Anthropic’s Claude models, and Claude Code is on that list.

More on this story

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