Microsoft ends OpenAI exclusivity in Office, adds rival Anthropic

Microsoft is ending its exclusive partnership with OpenAI in its Office 365 suite and will now incorporate AI models from Anthropic as well. The decision comes after internal testing showed that Anthropic's Claude Sonnet 4 model performs better in certain Office tasks, such as visual design and spreadsheet automation, where OpenAI's models struggle. This move is not seen as a negotiating tactic, according to sources familiar with the project. Anthropic has not yet responded to requests for comment.