Microsoft Graph MCP Server

A Model Context Protocol (MCP) server that exposes 20 tools letting Claude Desktop (or any MCP-compatible host) work with your Microsoft 365 data through the Microsoft Graph API — Outlook Mail, Calendar, OneDrive, Teams, and SharePoint.

Authentication uses the MSAL device-code (delegated) flow with a persistent, DPAPI-encrypted token cache, so you sign in once and the server reuses the cached session across restarts.

Tools (20)

Area	Tools
Outlook Mail	list messages, get message, send mail, create draft, search messages
Calendar	list events, get event, create event, update event, delete event
OneDrive	list root, list folder, search files, download file, upload file, create folder
SharePoint	list sites, get site details
Teams	list chats, send chat message

Prerequisites

Entra ID (Azure AD) app registration

1. Azure Portal → Microsoft Entra ID → App registrations → New registration.
2. Name: Microsoft Graph MCP Server.
3. Supported account types: Accounts in this organizational directory only (single-tenant) is recommended for the tightest sign-in surface. Note your Directory (tenant) ID.
4. Authentication → Advanced settings → set Allow public client flows to Yes (required for the device-code flow).
5. API permissions → add these delegated Microsoft Graph permissions (the least-privilege set matching the 20 tools):
   • User.Read
   • Mail.ReadWrite
   • Mail.Send
   • Calendars.ReadWrite
   • Files.ReadWrite
   • Sites.Read.All
   • Chat.ReadWrite
6. Click Grant admin consent — Sites.Read.All and Chat.ReadWrite require it.
7. Copy the Application (client) ID and Directory (tenant) ID.

Configuration

Create a .env from .env.example:

MICROSOFT_CLIENT_ID=your-application-client-id
MICROSOFT_TENANT_ID=your-directory-tenant-id   # your tenant ID (single-tenant) or "common" (multi-tenant/personal)

Install and build:

npm install
npm run build

First sign-in (run once in a terminal)

Start the server directly once in a terminal so you can see and complete the device-code prompt:

npm run start

The sign-in instructions print to stderr:

=========================================
MICROSOFT GRAPH AUTHENTICATION REQUIRED
To sign in, use a web browser to open https://microsoft.com/devicelogin and enter the code XXXXXXXXX.
=========================================

Open the link, enter the code, sign in, and consent. The token is then cached (DPAPI-encrypted, under %USERPROFILE%\.microsoft-graph-mcp\), so later runs — including when Claude Desktop launches the server — authenticate silently.

Why a terminal first? Claude Desktop captures the server's stderr into log files, so the device-code prompt is not visible in the chat UI. Completing the first sign-in in a terminal seeds the persistent cache; Claude Desktop then reuses it silently.

Claude Desktop configuration

Add the server to claude_desktop_config.json (on Windows: %APPDATA%\Claude\claude_desktop_config.json). Use the absolute path to your built build/index.js:

{
  "mcpServers": {
    "microsoft-graph": {
      "command": "node",
      "args": ["C:/path/to/microsoft-graph-mcp/build/index.js"],
      "env": {
        "MICROSOFT_CLIENT_ID": "your-application-client-id",
        "MICROSOFT_TENANT_ID": "your-directory-tenant-id"
      }
    }
  }
}

Restart Claude Desktop after editing the config.

Security notes

• Delegated permissions only. The server acts as the signed-in user and requests the least-privilege scope set above. No client secret is used or stored.
• Token cache is DPAPI-encrypted at rest (Windows) and lives in your user profile, never in the repository.
• Your .env is gitignored — never commit credentials.