Microsoft AI Updates: September 14, 2026

1. Grok Models Became Selectable Inside Copilot in Word, Excel, and PowerPoint

Microsoft added SpaceXAI’s Grok models to Copilot, rolling out through the Microsoft Frontier Program in Word, Excel, and PowerPoint. Access sits behind a dedicated admin setting that is disabled by default, and the models are hosted outside Microsoft infrastructure, so tenants opt in explicitly before any data reaches SpaceXAI. Grok is excluded from Frontier customers in the EU, EFTA countries, and the UK during the preview. Microsoft framed it as a limited release to gather usage data before widening availability to other Copilot surfaces, continuing its move to decouple Copilot from a single model provider. Source

2. GitHub Copilot’s HydraFusion Routes Each Coding Task Across Multiple Models at Runtime

GitHub opened a research preview of Project HydraFusion, which replaces a single static model behind Copilot with a runtime orchestrator that assembles an execution plan per task. It uses three patterns: single sends straightforward work to one model for speed, cascade has an efficient model draft and escalates to a stronger model only when quality gates fail, and critique pairs a drafting model with a separate critic that reviews output for structured revision. On TerminalBench 2.1, GitHub reports a 4.9 percentage point gain in verified task quality against a Claude Opus 5 baseline at 67% lower estimated cost; on CheckpointBench it roughly matched the baseline at 65% lower cost. The preview is available on all Copilot tiers through /experimental in the GitHub Copilot CLI, billed with standard token pricing. Source