M365 MCP

Powerful MCP server for Microsoft Graph API - a complete AI assistant toolkit for Outlook, Calendar, OneDrive, and Contacts.

Features

• Email Management: Read, send, reply, manage attachments, organize folders
• Calendar Intelligence: Create, update, check availability, respond to invitations
• OneDrive Files: Upload, download, browse with pagination
• Contacts: Search and list contacts from your address book
• Multi-Account: Support for multiple Microsoft accounts (personal, work, school)
• Unified Search: Search across emails, files, events, and people
• ⚡ High-Performance Caching: AES-256 encrypted cache with 300x performance improvement
• 🔒 Security & Compliance: GDPR and HIPAA compliant data encryption at rest

Quick Start

📚 See QUICKSTART.md for complete installation and setup guide.

TL;DR

# 1. Install
git clone https://github.com/robin-collins/m365-mcp.git
cd m365-mcp && uv sync

# 2. Configure (use .env.example template)
cp .env.example .env
# Edit .env with your M365_MCP_CLIENT_ID

# 3. Authenticate
uv run authenticate.py

# 4. Run
uv run m365-mcp

Claude Desktop

# Add M365 MCP server (replace with your Azure app ID)
claude mcp add m365-mcp -e M365_MCP_CLIENT_ID=your-app-id-here -- uvx --from git+https://github.com/robin-collins/m365-mcp.git m365-mcp

# Start Claude Desktop
claude

Usage Examples

# Email examples
> read my latest emails with full content
> reply to the email from John saying "I'll review this today"
> send an email with attachment to alice@example.com

# Calendar examples  
> show my calendar for next week
> check if I'm free tomorrow at 2pm
> create a meeting with Bob next Monday at 10am

# File examples
> list files in my OneDrive
> upload this report to OneDrive
> search for "project proposal" across all my files

# Multi-account
> list all my Microsoft accounts
> send email from my work account

Available Tools

Email Tools

• list_emails - List emails with optional body content
• get_email - Get specific email with attachments
• create_email_draft - Create email draft with attachments support
• send_email - Send email immediately with CC/BCC and attachments
• reply_to_email - Reply maintaining thread context
• reply_all_email - Reply to all recipients in thread
• update_email - Mark emails as read/unread
• move_email - Move emails between folders
• delete_email - Delete emails
• get_attachment - Get email attachment content
• search_emails - Search emails by query

Calendar Tools

• list_events - List calendar events with details
• get_event - Get specific event details
• create_event - Create events with location and attendees
• update_event - Reschedule or modify events
• delete_event - Cancel events
• respond_event - Accept/decline/tentative response to invitations
• check_availability - Check free/busy times for scheduling
• search_events - Search calendar events

Contact Tools

• list_contacts - List all contacts
• get_contact - Get specific contact details
• create_contact - Create new contact
• update_contact - Update contact information
• delete_contact - Delete contact
• search_contacts - Search contacts by query

File Tools

• list_files - Browse OneDrive files and folders
• get_file - Download file content
• create_file - Upload files to OneDrive
• update_file - Update existing file content
• delete_file - Delete files or folders
• search_files - Search files in OneDrive

Utility Tools

• unified_search - Search across emails, events, and files
• list_accounts - Show authenticated Microsoft accounts
• authenticate_account - Start authentication for a new Microsoft account
• complete_authentication - Complete the authentication process after entering device code

Cache Management Tools

• cache_get_stats - View cache statistics (size, entries, hit rate)
• cache_invalidate - Manually invalidate cache entries by pattern
• cache_task_enqueue - Queue background cache warming tasks
• cache_task_status - Check status of queued cache tasks
• cache_task_list - List all cache tasks by account or status

⚡ High-Performance Caching

M365 MCP includes an intelligent caching system that dramatically improves performance by reducing redundant API calls to Microsoft Graph.

Key Features

• 🔒 AES-256 Encryption: All cached data encrypted at rest using SQLCipher
• ⚡ 300x Performance Boost: Common operations like folder_get_tree go from 30s → <100ms
• 🧠 Intelligent TTL: Three-state cache (Fresh/Stale/Expired) with automatic refresh
• 📦 Automatic Compression: Large entries (≥50KB) automatically compressed (70-80% size reduction)
• 🔄 Cache Warming: Background pre-population on startup for instant responses
• 🎯 Smart Invalidation: Write operations automatically invalidate related caches
• 🌐 Multi-Account: Complete isolation between different accounts
• ✅ Compliance Ready: GDPR and HIPAA compliant data protection

Performance Benchmarks

Cache Configuration

The cache works automatically, but you can control its behavior:

# Use cache (default - recommended)
folder_get_tree(account_id, path="/Documents")

# Force refresh (bypass cache, update with fresh data)
folder_get_tree(account_id, path="/Documents", force_refresh=True)

# Disable cache for this request only
email_list(account_id, folder="inbox", use_cache=False)

Cache Security

• Encryption: AES-256 encryption via SQLCipher
• Key Storage: System keyring (macOS Keychain, Windows Credential Manager, Linux Secret Service)
• Fallback: Environment variable M365_MCP_CACHE_KEY for headless servers
• Compliance: GDPR Article 32 and HIPAA §164.312 compliant

Cache Management

View cache statistics:

stats = cache_get_stats()
# Returns: total_entries, size_bytes, hit_rate, oldest_entry, etc.

Manually invalidate cache:

# Invalidate all email caches
cache_invalidate("email_*")

# Invalidate specific account's caches
cache_invalidate("email_*", account_id="account-123")

📚 For complete cache documentation, see CLAUDE.md

Manual Setup

1. Azure App Registration

1. Go to Azure Portal → Microsoft Entra ID → App registrations
2. New registration → Name: m365-mcp
3. Supported account types: Personal + Work/School
4. Authentication → Allow public client flows: Yes
5. API permissions → Add these delegated permissions:

• offline_access (required for refresh tokens; the CLI retries against the consumers authority if a personal account flags it as reserved)
• Mail.ReadWrite
• Calendars.ReadWrite
• Files.ReadWrite
• Contacts.Read
• People.Read
• User.Read

1. Copy Application ID

2. Installation

git clone https://github.com/robin-collins/m365-mcp.git
cd m365-mcp
uv sync

3. Authentication

# Set your Azure app ID
export M365_MCP_CLIENT_ID="your-app-id-here"

# Run authentication script
uv run authenticate.py

# Follow the prompts to authenticate your Microsoft accounts

4. Claude Desktop Configuration

Add to your Claude Desktop configuration:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "microsoft": {
      "command": "uvx",
      "args": ["--from", "git+https://github.com/robin-collins/m365-mcp.git", "m365-mcp"],
      "env": {
        "M365_MCP_CLIENT_ID": "your-app-id-here"
      }
    }
  }
}

Or for local development:

{
  "mcpServers": {
    "microsoft": {
      "command": "uv",
      "args": ["--directory", "/path/to/m365-mcp", "run", "m365-mcp"],
      "env": {
        "M365_MCP_CLIENT_ID": "your-app-id-here"
      }
    }
  }
}

Transport Modes

M365 MCP supports two transport modes for different use cases:

stdio (Default) - For Desktop Apps

Use for: Claude Desktop, local MCP clients

Security: Inherently secure through process isolation (no authentication required)

# Default mode - no configuration needed
export M365_MCP_CLIENT_ID="your-app-id"
uv run m365-mcp

Streamable HTTP - For Web/API Access

Use for: Web applications, remote access, multi-client scenarios

Security: ⚠️ Requires authentication (bearer token or OAuth)

Protocol: Uses MCP Streamable HTTP (spec 2025-03-26+)

# Generate secure token
export MCP_AUTH_TOKEN=$(openssl rand -hex 32)

# Configure Streamable HTTP with bearer authentication
export M365_MCP_CLIENT_ID="your-app-id"
export MCP_TRANSPORT="http"
export MCP_AUTH_METHOD="bearer"
export MCP_HOST="127.0.0.1"
export MCP_PORT="8000"

# Start server
uv run m365-mcp

Client connection:

from mcp.client.http import http_client

async with http_client(
    "http://localhost:8000/mcp",
    headers={"Authorization": f"Bearer {your_token}"}
) as (read, write):
    # Use the session...

📚 See SECURITY.md for complete security guide and authentication options

Multi-Account Support

All tools require an account_id parameter as the first argument:

# List accounts to get IDs
accounts = list_accounts()
account_id = accounts[0]["account_id"]

# Use account for operations
send_email(account_id, "user@example.com", "Subject", "Body")
list_emails(account_id, limit=10, include_body=True)
create_event(account_id, "Meeting", "2024-01-15T10:00:00Z", "2024-01-15T11:00:00Z")

Development

# Run tests
uv run pytest tests/ -v

# Type checking
uv run pyright

# Format code
uvx ruff format .

# Lint
uvx ruff check --fix --unsafe-fixes .

Example: AI Assistant Scenarios

Smart Email Management

# Get account ID first
accounts = list_accounts()
account_id = accounts[0]["account_id"]

# List latest emails with full content
emails = list_emails(account_id, limit=10, include_body=True)

# Reply maintaining thread
reply_to_email(account_id, email_id, "Thanks for your message. I'll review and get back to you.")

# Forward with attachments
email = get_email(email_id, account_id)
attachments = [get_attachment(email_id, att["id"], account_id) for att in email["attachments"]]
send_email(account_id, "boss@company.com", f"FW: {email['subject']}", email["body"]["content"], attachments=attachments)

Intelligent Scheduling

# Get account ID first
accounts = list_accounts()
account_id = accounts[0]["account_id"]

# Check availability before scheduling
availability = check_availability(account_id, "2024-01-15T10:00:00Z", "2024-01-15T18:00:00Z", ["colleague@company.com"])

# Create meeting with details
create_event(
    account_id,
    "Project Review",
    "2024-01-15T14:00:00Z", 
    "2024-01-15T15:00:00Z",
    location="Conference Room A",
    body="Quarterly review of project progress",
    attendees=["colleague@company.com", "manager@company.com"]
)

Security Notes

• Tokens are cached locally in ~/.m365_mcp_token_cache.json
• Cache data is encrypted at rest using AES-256 in ~/.m365_mcp_cache.db
• Encryption keys stored securely in system keyring (or M365_MCP_CACHE_KEY env var)
• Use app-specific passwords if you have 2FA enabled
• Only request permissions your app actually needs
• Consider using a dedicated app registration for production

Troubleshooting

• Authentication fails: Check your CLIENT_ID is correct
• "Need admin approval": Use M365_MCP_TENANT_ID=consumers for personal accounts
• Missing permissions: Ensure all required API permissions are granted in Azure
• Token errors: Delete ~/.m365_mcp_token_cache.json and re-authenticate
• Cache issues: Delete ~/.m365_mcp_cache.db to reset cache (encryption key will regenerate)
• Slow first requests: Normal - cache warming runs in background, subsequent requests are fast

License

MIT