rockfordlhotka/calendar-mcp
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A unified Model Context Protocol (MCP) server for AI assistants to access multiple email and calendar accounts across Microsoft 365, Outlook.com, and Google Workspace.
Calendar & Email MCP Server
A unified Model Context Protocol (MCP) server that enables AI assistants to access multiple email and calendar accounts simultaneously across Microsoft 365 (multiple tenants), Outlook.com, and Google Workspace.
Overview
This MCP server provides AI assistants like Claude Desktop, ChatGPT, and GitHub Copilot with the ability to:
- Summarize emails across all your accounts
- View consolidated calendars from multiple sources
- Find available meeting times that don't conflict with any calendar
- Search emails across all inboxes simultaneously
- Coordinate scheduling by finding times and emailing participants (future phase)
Problem Statement
Professionals working with multiple organizations often juggle:
- Multiple Microsoft 365 tenants (different work accounts)
- Personal Outlook.com accounts
- Google Workspace accounts
Currently, no AI assistant can access all these services simultaneously in a multi-tenant scenario. This MCP server solves that problem.
Key Features
Phase 1 - Core Functionality (Current)
- Multi-account authentication and management
- Read-only email queries (unread, search, details)
- Read-only calendar queries (events, availability)
- Unified view aggregation across all accounts
- OpenTelemetry instrumentation for observability
Phase 2 - Write Operations (Planned)
- Send email from appropriate account (with smart routing)
- Create calendar events in appropriate calendar (with smart routing)
- Email threading and conversation tracking
- Advanced search with filters and date ranges
Phase 3 - AI-Assisted Scheduling (Future)
- Intelligent meeting time suggestions across calendars
- Automated meeting coordination via email
- Conflict detection and resolution
- Meeting preparation summaries
Architecture
This MCP server acts as an orchestration layer that:
- Exposes unified MCP tools to AI assistants
- Routes requests to appropriate accounts using intelligent routing
- Aggregates and deduplicates results from multiple sources
- Consumes existing Microsoft and Google MCP servers
See for detailed architecture and design specifications.
Technical Stack
- Language: C# / .NET 10
- MCP Server Framework: ModelContextProtocol NuGet package
- MCP Client Integration: Consumes existing Microsoft and Google MCP servers
- AI Routing: Configurable (Ollama, OpenAI, Anthropic, Azure, Custom)
- Authentication: OAuth 2.0 (Microsoft MSAL, Google OAuth)
- Observability: OpenTelemetry for logging, tracing, and metrics
Getting Started
Prerequisites
- .NET 10 SDK
- Microsoft 365 and/or Google Workspace accounts
- AI assistant that supports MCP (Claude Desktop, VS Code with Copilot, etc.)
Installation
(Coming soon - project is in early development)
Configuration
The server uses JSON-based configuration for:
- Multiple account definitions (M365 tenants, Outlook.com, Google)
- Smart router AI backend selection (local Ollama or cloud APIs)
- OpenTelemetry exporters and settings
See for configuration examples.
Use Cases
Email Management
"Summarize all my unread emails from the last 24 hours"
"What emails do I have about the Acme project?"
"Search for emails from john@example.com across all my accounts"
Calendar Management
"Show me my calendar for tomorrow across all accounts"
"Find 1-hour slots next week where I'm free"
"Do I have any conflicts on Friday?"
Future: Meeting Coordination
"Schedule a 1-hour meeting with John and Sarah next week"
→ AI finds your availability, emails participants, proposes times
Project Status
🚧 Early Development - This project is in the design and initial implementation phase.
Contributing
Contributions are welcome! This is an open-source project aimed at solving a real problem for professionals managing multiple work contexts.
Target Audience
- Consultants managing multiple client accounts
- Contractors with multiple work engagements
- Professionals with separate work/personal accounts
- Anyone in multi-tenant scenarios
License
MIT License - see file for details.
Related Projects
This server leverages these excellent MCP implementations:
- microsoft-mcp by elyxlz
- google_workspace_mcp by taylorwilsdon
Support
- Open an issue for bugs or feature requests
- See for architecture details
- Check discussions for questions and ideas
Note: This project is not affiliated with Microsoft, Google, or Anthropic.