Microsoft adds Claude Sonnet to M365 Copilot — first Anthropic model in the Office suite

Microsoft announced on March 9 that Anthropic's Claude Sonnet models will be available to Microsoft 365 Copilot users. This is the first time an Anthropic model has been integrated into the M365 suite — the productivity platform used by more than 345 million paid seats across enterprise and SMB customers. Microsoft Copilot has previously run primarily on OpenAI's GPT models, with alternatives available through Copilot Studio for custom deployments.

Microsoft is the most important distribution channel in enterprise software. Adding Claude Sonnet to M365 Copilot gives Anthropic passive access to the largest concentrated pool of knowledge-worker seats in the world — without Anthropic having to build its own enterprise sales motion for each account.