Microsoft adds Anthropic’s Claude models to Office 365 Copilot

Microsoft has added Anthropic’s Claude Sonnet 4 and Claude Opus 4.1 AI models to Microsoft 365 Copilot, marking the first time the company has expanded beyond OpenAI’s models for its flagship productivity suite. This strategic shift reflects Microsoft’s growing confidence in Anthropic’s capabilities and signals a broader diversification strategy as the company seeks to offer customers the best AI models regardless of their origin.

What you should know: Microsoft is integrating Anthropic’s models into specific areas of Microsoft 365 Copilot while maintaining OpenAI as the primary foundation.

• Claude models are now available in Microsoft’s Researcher agent and Copilot Studio, the platform for building custom AI agents.
• Users can switch between OpenAI and Anthropic models within the Researcher tool through a “Try Claude” button.
• The integration allows customers to mix and match models from different providers for specific tasks.

The big picture: Microsoft is increasingly favoring Anthropic over OpenAI across multiple products, suggesting a significant strategic realignment.

• GitHub Copilot paid users now “primarily rely on Claude Sonnet 4” when using Visual Studio Code’s automatic AI model selection.
• Reports indicate Microsoft plans to use Anthropic’s models in Excel and PowerPoint after finding they outperformed OpenAI’s offerings.
• This expansion comes just one week after Microsoft started prioritizing Anthropic in Visual Studio Code.

Technical implementation: The integration maintains existing cloud partnerships despite competitive tensions.

• Anthropic’s models will continue running on Amazon Web Services, Microsoft’s primary cloud rival.
• Microsoft accesses Claude through Anthropic’s API, similar to any third-party developer.
• This mirrors Microsoft’s previous arrangement with xAI to host Grok 3 models on Azure.

What they’re saying: Microsoft executives frame the move as expanding customer choice while maintaining OpenAI partnerships.

• “Copilot will continue to be powered by OpenAI’s latest models, and now our customers will have the flexibility to use Anthropic models too,” explains Charles Lamanna, president of Microsoft’s business and industry Copilot team.
• “The addition of Claude Sonnet 4 and Claude Opus 4.1 advances our commitment to bring the best AI innovation from across the industry to Microsoft 365 Copilot, tuned for work and tailored to your business needs.”
• “This is just the beginning — we’re committed to delivering model innovation at speed,” Lamanna teases.

Availability: The Claude integration is rolling out through Microsoft’s opt-in programs.

• Claude in Researcher is available today via the Frontier program to Microsoft 365 Copilot licensed customers.
• Copilot Studio users can also opt in to access Anthropic’s models.
• Future expansions to additional Microsoft 365 applications are expected.