OutlookMCPServer is an MCP server that gives Claude Desktop access to Microsoft 365 mail, calendar, and files through the Microsoft Graph API. It leverages the modern Microsoft Graph SDK (msgraph) and Azure Identity's DeviceCodeCredential with persistent token caching to authenticate against Azure AD. The server exposes an MCP-compliant interface via FastMCP, enabling Claude to read and manage mail, calendar events, and file metadata from OneDrive and SharePoint. It runs locally on macOS and is intended for use with Claude Desktop. Authentication requires an Azure-registered application and tenant admin consent for Graph scopes (e.g., Mail.Read, Calendars.Read). Setup includes creating an auth_cache directory to persist authentication state and a .env file defining AZURE_CLIENT_ID, AZURE_TENANT_ID, and AZURE_GRAPH_SCOPES. On first run, the application uses Device Code flow and will create auth_record.json in auth_cache if successful. The project includes a modular folder structure under mcpserver/graph with services for mail, calendar, files, and a controller/server that ties MCP requests to Graph API calls. Getting started instructions cover cloning, virtual env setup with uv, and running via MCP Inspector for debugging.