Microsoft Build 2026: MAI-Thinking-1 Reasoning Model and Execution Containers

Microsoft Blog·medium signal

At Build 2026 (June 2), Microsoft's AI Superintelligence Team released MAI-Thinking-1, a 35B-active-parameter reasoning model with a 256K context window, alongside MAI-Code-1-Flash (natural-language-to-source-code) — part of a push to lower developer costs and reduce reliance on OpenAI. Microsoft Execution Containers (MXC) also entered preview, offering enterprise-grade sandboxed environments for running agents. Signals Microsoft building a full first-party agent stack rather than reselling OpenAI.