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: Encrypted-at-rest cache designed for GDPR/HIPAA-aligned deployments

Related MCP server: Microsoft MCP

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

• email_list - List emails with optional body content

• email_get - Get a specific email with attachments

• email_create_draft - Create an email draft with attachment support

• email_send - Send email immediately with CC/BCC and attachments

• email_reply - Reply while maintaining thread context

• email_reply_all - Reply to all recipients in a thread

• email_forward - Forward an email

• email_update - Update message metadata

• email_move - Move email between folders

• email_delete - Delete email

• email_get_attachment - Download an attachment to a validated local path

• email_mark_read - Mark email read or unread

• email_flag - Add or clear follow-up flags

• email_add_category - Add an Outlook category

• email_archive - Archive an email

• search_emails - Search emails by query

Calendar Tools

• calendar_list_calendars - List calendars

• calendar_create_calendar - Create a calendar

• calendar_delete_calendar - Delete a calendar

• calendar_list_events - List calendar events with details

• calendar_get_event - Get specific event details

• calendar_create_event - Create events with location and attendees

• calendar_update_event - Reschedule or modify events

• calendar_delete_event - Cancel events

• calendar_respond_event - Accept, decline, or tentatively accept invitations

• calendar_forward_event - Forward an event invitation

• calendar_propose_new_time - Propose a new meeting time

• calendar_get_free_busy - Get free/busy schedules

• calendar_check_availability - Check free/busy times for scheduling

• search_events - Search calendar events

Contact Tools

• contact_list - List all contacts

• contact_get - Get specific contact details

• contact_create - Create a new contact

• contact_update - Update contact information

• contact_delete - Delete a contact

• contact_create_list - Create a contact list

• contact_add_to_list - Add contacts to a contact list

• contact_export - Export contacts

• search_contacts - Search contacts by query

File Tools

• file_list - Browse OneDrive files and folders

• file_get - Download file content

• file_create - Upload files to OneDrive

• file_update - Update existing file content

• file_delete - Delete files

• file_copy - Copy files

• file_move - Move files

• file_rename - Rename files

• file_share - Create sharing links

• file_download_url - Get a temporary download URL

• folder_list - List OneDrive folders

• folder_get - Get folder metadata

• folder_get_tree - Build a recursive folder tree

• folder_create - Create folders

• folder_move - Move folders

• folder_rename - Rename folders

• folder_delete - Delete folders

• search_files - Search files in OneDrive

Email Folder And Rule Tools

• emailfolders_list - List mail folders

• emailfolders_get - Get mail folder metadata

• emailfolders_get_tree - Build a recursive mail folder tree

• emailfolders_create - Create mail folders

• emailfolders_rename - Rename mail folders

• emailfolders_move - Move mail folders

• emailfolders_delete - Delete mail folders

• emailfolders_mark_all_as_read - Mark a folder as read

• emailfolders_empty - Empty a mail folder

• emailrules_list - List inbox rules

• emailrules_get - Get a rule

• emailrules_create - Create a rule

• emailrules_update - Update a rule

• emailrules_delete - Delete a rule

• emailrules_move_top, emailrules_move_bottom, emailrules_move_up, emailrules_move_down - Reorder rules

Utility Tools

• search_unified - Search across emails, events, files, and contacts

• account_list - Show authenticated Microsoft accounts

• account_authenticate - Start authentication for a new Microsoft account

• account_complete_auth - Complete authentication after entering the device code

• server_get_version - Return server version metadata

Cache Management Tools

• cache_get_stats - View cache statistics (size, entries, hit rate)

• cache_invalidate - Manually invalidate cache entries by pattern

• cache_task_get_status - Check status of queued cache tasks

• cache_task_list - List all cache tasks by account or status

• cache_warming_status - View cache warming/background refresh 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: Cached data is encrypted at rest using SQLCipher by default

• ⚡ 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)

• 🔄 Optional Cache Warming: Set M365_MCP_CACHE_WARMING=true to start the background worker, startup warming, and stale-cache refresh queue

• 🎯 Smart Invalidation: Write operations automatically invalidate related caches

• 🌐 Multi-Account: Complete isolation between different accounts

• ✅ Compliance Ready: Encryption and retention controls for regulated deployments

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. If SQLCipher is missing while encryption is enabled, startup fails instead of silently using plaintext.

• Key Storage: System keyring (macOS Keychain, Windows Credential Manager, Linux Secret Service)

• Fallback: Environment variable M365_MCP_CACHE_KEY for headless servers; if neither keyring nor the env var is available, a generated ephemeral key is used with a warning

• Plaintext Mode: Only used when cache encryption is explicitly disabled by code, primarily for tests and diagnostics

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

6. 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

# Force-refresh a cached token to verify silent renewal
uv run authenticate.py --re-auth <account-id-or-email>

# Remove an account, its tokens, and its local data cache
uv run authenticate.py --remove <account-id-or-email>

# 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": {
    "m365-mcp": {
      "command": "uv",
      "args": ["--directory", "c:\\projects\\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

Account-scoped tools require an account_id argument. Established public tool signatures keep their historical parameter order for compatibility, so use the tool schema or examples for exact ordering instead of assuming account_id is always first.

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

# Use account for operations
email_send(account_id, "user@example.com", "Subject", "Body", confirm=True)
email_list(account_id, limit=10, include_body=True)
calendar_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 = account_list()
account_id = accounts[0]["account_id"]

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

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

# Download attachments locally
email = email_get(email_id, account_id)
for attachment in email["attachments"]:
    email_get_attachment(
        email_id,
        attachment["id"],
        f"C:/Users/you/Downloads/{attachment['name']}",
        account_id,
    )

Intelligent Scheduling

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

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

# Create meeting with details
calendar_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 SQLCipher in ~/.m365_mcp_cache.db

• Encryption keys are loaded from system keyring or M365_MCP_CACHE_KEY; generated non-persistent keys produce a warning

• SQLCipher is required when cache encryption is enabled; plaintext cache mode is only used when explicitly requested by code

• 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. If the stored key cannot open the database, the cache is recreated automatically.

• Slow first requests: Normal on a cold cache. Set M365_MCP_CACHE_WARMING=true to enable startup warming and stale-cache background refresh.

License

MIT