Microsoft has added Anthropic's Claude Opus 5 to Microsoft 365 Copilot, expanding its enterprise AI platform with advanced reasoning, writing, coding, and analytical capabilities across productivity apps. The move is part of Microsoft's multi-model AI strategy, allowing organizations to use Anthropic's flagship model within the Microsoft 365 ecosystem without leaving it. Claude Opus 5 is now available in Microsoft 365 Copilot, enabling enterprise customers to leverage the model for tasks such as document creation, research, coding, spreadsheet analysis, presentation design, and strategic planning. The model offers improvements in advanced reasoning, long-form writing, coding assistance, technical documentation, research workflows, spreadsheet analysis, business planning, and complex problem-solving. It can be used across Microsoft Word, Microsoft Excel, Microsoft PowerPoint, Microsoft Outlook, Microsoft Teams, Microsoft 365 Copilot Chat, and the Microsoft 365 Copilot app. Microsoft stated that organizations will continue to benefit from the same enterprise-grade security, compliance, and governance protections already built into Microsoft 365 Copilot, including enterprise security controls, compliance policies, data governance, administrative management, and existing Microsoft 365 protections.