Microsoft reportedly to use Anthropic’s Claude in some Office 365 Copilot features

According to a report by The Information (covered by Engadget), Microsoft plans to begin using Anthropic’s latest Claude models — notably Claude Sonnet 4 — to power some Copilot features across Office 365 apps like Word, Excel, Outlook and PowerPoint. Microsoft currently uses OpenAI models for most Copilot features.

Key points

• Report says Microsoft will announce the change “in the coming weeks.”
• Microsoft denies the decision is driven by animosity, saying OpenAI remains a partner on frontier models.
• Sources told The Information Microsoft believes Claude Sonnet 4 “performs better in subtle but important ways” (e.g., producing more aesthetically pleasing PowerPoint slides).
• Microsoft reportedly won’t raise Copilot pricing — still $30/user/month — despite paying Anthropic via AWS for Claude access, whereas Microsoft can access OpenAI models under its investment terms.

Why it matters

This could signal a deeper strategic divergence between Microsoft and OpenAI, even as both publicly emphasize ongoing partnership. For users, it may mean different AI behaviors and outputs inside Office apps depending on the underlying model.

Sources

• Engadget coverage: Engadget

If you want more links or a deeper breakdown (including The Information’s original story), reply and I’ll add them.