Microsoft unveils AI agent sandbox, Scout at Build 2026

Microsoft Unveils AI Agent Infrastructure at Build 2026, Including MXC Sandbox and Scout Assistant

Microsoft opened its Build 2026 developer conference on Tuesday at the Fort Mason Center in San Francisco with a suite of announcements that position Windows as an operating system built to run AI agents, not merely host them. CEO Satya Nadella used the keynote to lay out a vision centered on agentic AI — software that acts on behalf of users rather than simply answering questions.

MXC and the Agent Runtime

Among the day’s most notable reveals, Microsoft introduced MXC, an OS-level sandbox for AI agents in Windows that provides enterprises with secure runtime controls, identity management, and policy enforcement. OpenAI and Nvidia are already on board as partners, according to VentureBeat. The announcement builds on a broader Windows Agent Framework that introduces new APIs letting AI agents integrate directly with the Windows shell, task scheduler, and security model as registered system-level services with defined permissions and audit trails. Microsoft’s Defender and Intune can detect and govern unmanaged agents, giving IT administrators the same visibility over AI agents they have over traditional software.venturebeat

The Windows Agent Runtime, the execution layer underpinning MXC, is expected to be available as an Insider preview this month, with initial support limited to text-based agents.aitoolsrecap

Scout and the Copilot Super App

Microsoft also introduced Scout, described as an always-on AI agent that operates within internal email and calendar systems like a regular employee. Scout is part of a broader Copilot “super app” strategy that unifies Copilot, Cowork, and GitHub Copilot into a single interface. The Verge reported ahead of the event that Microsoft planned to debut the consolidated app, though availability may not come until later this year.theverge

Project Solara and New Hardware

Project Solara, announced during the keynote, is a chip-to-cloud platform designed for environments where traditional PCs are impractical. Rather than a coding model as some pre-event speculation suggested, Solara encompasses new form factors — devices resembling a smart clock and a work ID badge — connected through Azure. Nvidia CEO Jensen Huang made a guest appearance to discuss RTX Spark, an Arm-based platform pairing a 20-core Grace CPU with a Blackwell RTX GPU and up to 128GB of unified memory, which Microsoft showcased in a new Surface RTX Spark dev box offering one petaflop of local AI compute.tomsguide

Microsoft also revealed its first reasoning model, MAI-Thinking-1, and new Azure Cobalt 200 VMs delivering a 50% performance improvement for agentic workloads. The conference continues through Wednesday.business-standard