Microsoft plans to integrate Anthropic's AI technology into Office 365, diversifying beyond its reliance on OpenAI after investing nearly $13 billion in the latter. Developers note that Anthropic's Claude Sonnet 4 outperforms OpenAI's ChatGPT-5, particularly in Excel command processing and PowerPoint presentation creation. Despite this expansion, Microsoft will not alter its Office pricing and will incur fees to access Anthropic’s models via Amazon Web Services, one of Anthropic’s major investors.