Microsoft swaps Office AI models

Microsoft has begun routing some AI work inside Excel and Outlook to its own MAI models instead of systems from OpenAI and Anthropic, according to a Bloomberg report published July 7. Tens of thousands of prompts a week in the spreadsheet and email products are now being completed with Microsoft-built models, Bloomberg reported, citing a person familiar with the work. A Microsoft spokesperson declined to comment. The reported change affects widely used workplace software at a time when Microsoft is still adding outside models to parts of Microsoft 365 Copilot. ### Which Office features are reportedly moving first? Bloomberg reported that Excel and Outlook are the first named products where Microsoft has started replacing outside models with in-house ones. The report said the shift covers some AI prompts in those applications rather than a full replacement of all model usage. The two products matter because Excel and Outlook sit at the center of many Microsoft 365 deployments. Bloomberg said the prompts being rerouted number in the tens of thousands each week, though it also said MAI still accounts for only a small share of Microsoft’s overall AI usage. ### Is Microsoft cutting ties with OpenAI and Anthropic? (finance.yahoo.com) Microsoft is not exiting those relationships based on the reporting now in public. Bloomberg said Excel and Outlook had previously relied more heavily on models from OpenAI and Anthropic, which indicates the change is partial and workload-specific rather than a clean break. (finance.yahoo.com) Microsoft’s own product updates show outside models are still present in its commercial AI stack. In a May 29 Microsoft 365 Copilot update, Microsoft said Anthropic’s Claude Opus 4.8 was available in Microsoft 365 Copilot and was rolling out to Copilot Chat, Copilot Studio early release environments, Excel and PowerPoint for licensed users. (finance.yahoo.com) ### Why is Microsoft doing this now? Mustafa Suleyman, Microsoft’s AI model chief, said in June that the company was trying to reduce spending on Anthropic by using more MAI models, according to Bloomberg. Bloomberg also reported that Microsoft uses large volumes of AI tokens in products such as Copilot and is trying to avoid paying whatever leading labs decide to charge when current commercial arrangements change. (techcommunity.microsoft.com) At Microsoft’s Build conference in June, the company announced seven new AI models, Bloomberg reported. Bloomberg said one of those models was presented as matching the coding ability of a prior-generation Anthropic model at lower cost. ### Does this line up with Microsoft’s broader product rollout? Microsoft’s current release notes for Microsoft 365 Copilot say Copilot features are introduced with a “safe deployment model,” first reaching a subset of users within a tenant before expanding across the organization. (finance.yahoo.com) That staged rollout process fits with a report of selective prompt routing inside large enterprise products rather than a platform-wide switch all at once. The same release notes show Microsoft continuing to ship new Copilot controls and agent features through July 1 updates, including watermark controls for AI-generated audio and video and task-status visibility for long-running agents. Those updates indicate Microsoft is still actively changing how Copilot behaves inside enterprise environments while model choices evolve underneath. (learn.microsoft.com) ### Where else are Microsoft’s own models showing up? Bloomberg reported that Microsoft’s MAI models are already available inside GitHub Copilot. The report also said Suleyman has said a Microsoft-built transcription model will begin being used with Teams and other products in the coming months. Those details suggest the Excel and Outlook changes are part of a broader product-by-product deployment. (learn.microsoft.com) Microsoft’s next visible checkpoints are likely to come through future Microsoft 365 Copilot release notes, Build follow-ups, or any public comment from Microsoft, OpenAI or Anthropic. (finance.yahoo.com)