Yesterday in AI: 02 June 2026 — Microsoft Cuts the OpenAI Cord at Build
Microsoft launched 7 in-house MAI models at Build 2026 — including a coding model live across all Copilot tiers today and GPT-4 Turbo gone by August; Anthropic expanded Project Glasswing's Claude Mythos to NATO and 150 orgs after flagging 23K+ vulnerabilities; MiniMax M3 claims frontier coding on open weights.
By OMC Editorial on 2026-06-03
TL;DR — Microsoft unveiled 7 in-house AI models at Build 2026, rolling MAI-Code-1-Flash out to all GitHub Copilot tiers immediately while Project Polaris retires GPT-4 Turbo by August; Anthropic expanded Project Glasswing to 150 organizations including NATO and ENISA after Claude Mythos flagged 23,019 vulnerabilities in 1,000+ open-source projects; MiniMax M3 launched as the first open-weight model claiming frontier-level coding at 59% SWE-Bench Pro, with weights due on Hugging Face by June 11.
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1️⃣ Microsoft Build 2026: 7 In-House Models, GPT-4 Turbo Out by August
- What: Microsoft unveiled 7 new MAI models at Build 2026 on June 2, led by MAI-Thinking-1 35B active parameters, no OpenAI training data and MAI-Code-1-Flash 5B, rolling out to all Copilot tiers today; Project Polaris will replace GPT-4 Turbo as GitHub Copilot's default engine by August 2026.
- Why it matters: This ends GitHub Copilot's OpenAI dependency — the world's most-used AI coding assistant will run entirely on Microsoft's own stack within two months.
- Key number: MAI-Code-1-Flash scores 51.2% on SWE-Bench Pro vs 35.2% for Claude Haiku 4.5, a 16-point gap, while using 60% fewer tokens on complex tasks.
MAI-Thinking-1 is a sparse Mixture-of-Experts reasoning model with 35B active parameters and a 256K context window, trained from scratch on commercially licensed data with no distillation from third-party models. Microsoft reports 97.0% on AIME 2025 and a match to Claude Opus 4.6 on SWE-Bench Pro; in blind side-by-side evaluations by independent rater Surge, it outperformed Claude Sonnet 4.6.
MAI-Code-1-Flash is available today across Free, Pro, Pro+, and Max GitHub Copilot plans. Adaptive solution length control lets it stay concise for simple requests and expand its reasoning budget for harder problems. Project Polaris completes its rollout in August, ending Copilot's OpenAI model dependency entirely.
Also shipped at Build: multi-agent VS Code with a planner-and-specialist subagent arc