Modular Outlook MCP Server

What is Modular Outlook MCP Server?

Modular Outlook MCP Server is an MCP (Model Context Protocol) server that connects Claude with Microsoft 365 services through the Microsoft Graph API and Power Automate API. It provides tools for managing Outlook (email, calendar, folders, rules), OneDrive (files, sharing), and Power Automate (flows, environments, run history). Designed for developers and administrators who want to interact with M365 data directly from Claude.

How to use Modular Outlook MCP Server?

Install dependencies with npm install, then register an Azure AD app with required permissions and configure environment variables in .env. Start the auth server with npm run auth-server, use the authenticate tool in Claude to get an OAuth URL, sign in, and tokens are saved to ~/.outlook-mcp-tokens.json. Add the server to Claude Desktop config with command: "node" and the path to index.js.

Key features of Modular Outlook MCP Server

• OAuth 2.0 authentication with Microsoft Graph and Flow APIs
• Email management: list, search, read, send, mark as read/unread
• Calendar management: list, create, accept, decline, delete events
• OneDrive integration: list, search, upload, download, share files
• Power Automate: list environments/flows, trigger runs, view history
• Test mode with simulated responses for development

Use cases of Modular Outlook MCP Server

• Automate email triage and rule creation via Claude
• Manage calendar events and responses without leaving chat
• Upload and share OneDrive files on demand
• Trigger Power Automate flows and check their run history
• Search and organize emails across folders

FAQ from Modular Outlook MCP Server

What Azure permissions are required?

Delegated permissions for User.Read, Mail.Read, Mail.ReadWrite, Mail.Send, Calendars.Read, Calendars.ReadWrite, Files.Read, Files.ReadWrite, and offline_access are needed. For Power Automate, additional Azure AD configuration with https://service.flow.microsoft.com//.default scope is required.

How do I start the authentication process?

Run npm run auth-server and use the authenticate tool in Claude. Visit the provided URL, sign in with your Microsoft account, and tokens are saved locally.

What are the limitations of Power Automate support?

Only solution-aware flows are accessible, only manual-trigger flows can be run via API, and an environment ID is required for most operations.

How can I run the server without real API calls?

Set USE_TEST_MODE=true in .env or pass the environment variable USE_TEST_MODE=true in the Claude Desktop config. This uses mock data for all operations.

How do I fix common authentication errors?

If you see "Invalid client secret", ensure you are using the client secret VALUE (not the Secret ID). For "Authentication required", delete ~/.outlook-mcp-tokens.json and re-authenticate.