MS365 Email Server

A Python-based Model Context Protocol (MCP) server for Microsoft 365 Outlook email operations. This server uses OAuth 2.0 Client Credentials Flow for authentication, making it ideal for autonomous agents and server-to-server scenarios.

Built with FastMCP for simplified server implementation, following the pattern used by AWS API MCP Server.

Features

This MCP server provides the following email operations:

• list-mail-messages - List mail messages from inbox or a specific folder
• list-mail-folders - List all mail folders
• list-mail-folder-messages - List messages from a specific folder
• get-mail-message - Get a specific mail message by ID
• send-mail - Send an email
• delete-mail-message - Delete a mail message
• create-draft-email - Create a draft email
• move-mail-message - Move a mail message to another folder

Authentication

This server uses OAuth 2.0 Client Credentials Flow (app-only authentication), which is perfect for autonomous agents and background services. No user interaction is required.

Reference: Microsoft Graph - Get access without a user

Prerequisites

1. Azure App Registration

You need to register an application in Azure AD with Application permissions (not Delegated):

1. Go to Azure Portal → Azure Active Directory → App registrations
2. Create a new registration
3. Note down:
   • Application (client) ID
   • Directory (tenant) ID
4. Create a client secret:
   • Go to Certificates & secrets → New client secret
   • Copy the secret value immediately (it won't be shown again)
5. Configure API permissions:
   • Go to API permissions → Add a permission → Microsoft Graph
   • Select Application permissions (not Delegated)
   • Add the following permissions:
     • Mail.Read - Read user mail
     • Mail.ReadWrite - Read and write user mail
     • Mail.Send - Send mail as user
   • Grant admin consent (required for application permissions)

Important: Application permissions require administrator consent. The app must be granted consent before it can use these permissions.

Reference: Microsoft Graph - Configure permissions

2. Environment Variables

MS365_CLIENT_ID=your-azure-ad-client-id
MS365_CLIENT_SECRET=your-azure-ad-client-secret
MS365_TENANT_ID=your-tenant-id
# Optional: For Government Cloud
MS365_CLOUD_TYPE=gov  # Options: "commercial" (default), "gov", "government", "usgov"
# Optional: For shared mailboxes (required for Client Credentials Flow)
[email protected]  # UserPrincipalName or Graph ID of the shared mailbox

Important for Shared Mailboxes: When using Client Credentials Flow (app-only authentication), you must provide MS365_USER_IDENTIFIER because /me/ endpoints don't work without a signed-in user. Use the UserPrincipalName (e.g., [email protected]) or the Graph ID of the shared mailbox.

Local Development

This project uses UV for dependency management, similar to the AWS API MCP Server.

1. Install UV

# Install UV using pip
pip install uv

# Or using Homebrew (macOS)
brew install uv

# Or using the official installer
curl -LsSf https://astral.sh/uv/install.sh | sh

2. Install Dependencies

# Install project dependencies
uv sync

# Or install in development mode with dev dependencies
uv sync --dev

3. Set Environment Variables

export MS365_CLIENT_ID="your-client-id"
export MS365_CLIENT_SECRET="your-client-secret"
export MS365_TENANT_ID="your-tenant-id"
export PORT="8100"  # Optional, defaults to 8100
export HOST="0.0.0.0"  # Optional, defaults to 0.0.0.0
export LOG_LEVEL="INFO"  # Optional, defaults to INFO
export STATELESS_HTTP="true"  # Optional, defaults to true

4. Run the Server

Using UV (recommended):

# Run using UV
uv run ms365-email-mcp-server

# Or run directly with Python (after uv sync)
python -m ms365_email_mcp_server.server

The server will start on http://localhost:8100 with:

• SSE endpoint: http://localhost:8100/message
• Health check: http://localhost:8100/health

Docker Usage

Build the Docker Image

The Dockerfile uses UV for dependency management:

docker build -t email-mcp-server .

Run the Container

docker run -d \
  -p 8100:8100 \
  -e MS365_CLIENT_ID="your-client-id" \
  -e MS365_CLIENT_SECRET="your-client-secret" \
  -e MS365_TENANT_ID="your-tenant-id" \
  -e MS365_CLOUD_TYPE="commercial" \
  email-mcp-server

Using Docker Compose

Create a .env file:

MS365_CLIENT_ID=your-client-id
MS365_CLIENT_SECRET=your-client-secret
MS365_TENANT_ID=your-tenant-id
MS365_CLOUD_TYPE=commercial

Then run:

docker-compose up

Or in detached mode:

docker-compose up -d

MCP Client Configuration

HTTP/SSE Endpoint

The server runs as an HTTP/SSE server. Connect to it using:

• SSE Endpoint: http://localhost:8100/message
• Health Check: http://localhost:8100/health

Using with MCP Clients

Option 1: HTTP/SSE Transport (Recommended)

For clients that support HTTP/SSE transport, configure:

{
  "mcpServers": {
    "ms365-email": {
      "url": "http://localhost:8100/message",
      "transport": "sse"
    }
  }
}

Option 2: Using UV (for stdio transport)

If you want to use UV to run the server (similar to AWS API MCP Server), you can configure:

{
  "mcpServers": {
    "ms365-email": {
      "command": "uvx",
      "args": [
        "ms365-email-mcp-server@latest"
      ],
      "env": {
        "MS365_CLIENT_ID": "your-client-id",
        "MS365_CLIENT_SECRET": "your-client-secret",
        "MS365_TENANT_ID": "your-tenant-id",
        "LOG_LEVEL": "INFO"
      }
    }
  }
}

Note: This requires the package to be published to PyPI. For local development, use Option 1 or run the server manually with uv run ms365-email-mcp-server.

API Reference

Microsoft Graph API Endpoints Used

• List Messages: GET /me/messages
• Send Mail: POST /me/sendMail
• Get Message: GET /me/messages/{id}
• Delete Message: DELETE /me/messages/{id}
• Create Draft: POST /me/messages
• Move Message: POST /me/messages/{id}/move
• List Folders: GET /me/mailFolders

Government Cloud Support

For Azure Government Cloud, set:

export MS365_CLOUD_TYPE="gov"

This will use:

• Authority: https://login.microsoftonline.us
• Graph API: https://graph.microsoft.us

Security Notes

• Never commit your client secrets to version control
• Use environment variables or secret management systems
• Rotate client secrets regularly
• Consider using managed identities in Azure for production
• Application permissions require administrator consent

Troubleshooting

"Failed to acquire token"

• Verify your MS365_CLIENT_ID, MS365_CLIENT_SECRET, and MS365_TENANT_ID are correct
• Ensure admin consent has been granted for the application permissions
• Check that the client secret hasn't expired

"Insufficient privileges"

• Verify that admin consent has been granted for all required permissions
• Check that you're using Application permissions (not Delegated permissions)

"Invalid tenant"

• Verify your MS365_TENANT_ID is correct
• For Government Cloud, ensure MS365_CLOUD_TYPE is set to "gov"

License

MIT