Google Meet Scheduler Agent (FastMCP + LangGraph + LangChain)

An AI scheduling assistant built with LangGraph, LangChain, and a custom FastMCP Server to manage Google Calendar events and generate Google Meet video conferencing links.

🌟 Key Features

1. Custom FastMCP Server (mcp_server.py):

   • list_upcoming_events: Browse calendar schedule.

   • check_availability: Query Google Calendar freebusy for user & attendees.

   • create_meeting: Create calendar events with auto-generated Google Meet (hangoutsMeet) links (conferenceDataVersion=1).

   • update_meeting: Reschedule or update event details.

   • delete_meeting: Cancel events and auto-notify participants.

   • get_meeting_details: Inspect meeting details, RSVP statuses, and Meet URLs.

2. LangGraph Agent (agent.py):

   • Contextual date/time parsing (converts relative times like "tomorrow 3 PM" to exact ISO-8601 strings in user timezone).

   • Multi-turn conversation state checkpointing via MemorySaver.

   • Tool calling integration using LangChain.

📁 Project Structure

google-meet-scheduler/
├── auth.py              # Google OAuth 2.0 & Calendar API v3 service helper
├── mcp_server.py        # FastMCP Server registering Google Meet/Calendar tools
├── agent_state.py       # LangGraph state schema (SchedulerState)
├── agent.py             # LangGraph state graph, system prompt, and tools node
├── main.py              # Interactive CLI Chat interface
├── .env.example         # Template for environment variables
├── requirements.txt     # Python dependencies
└── README.md            # Documentation & setup guide

🚀 Quick Start Guide

1. Install Dependencies

python -m venv venv
# On Windows:
venv\Scripts\activate
# On macOS/Linux:
source venv/bin/activate

pip install -r requirements.txt

2. Set Up Google Cloud Credentials

1. Go to Google Cloud Console.

2. Create a new project (e.g. Google Meet MCP).

3. Enable Google Calendar API.

4. Go to APIs & Services > Credentials -> Create Credentials -> OAuth client ID.

5. Select Application type: Desktop app.

6. Download the JSON file, rename it to credentials.json, and place it in the project root directory.

3. Configure Environment Variables

Copy .env.example to .env:

cp .env.example .env

Fill in your API keys in .env:

DEFAULT_TIMEZONE=Asia/Kolkata
GEMINI_API_KEY=your_gemini_api_key
# or
OPENAI_API_KEY=your_openai_api_key

4. Run the Agent

python main.py

Note: On your first run, a browser window will open asking you to log into your Google account and authorize Calendar access. Once approved, a token.json file will be created for seamless subsequent authentication.

🛠️ Testing the FastMCP Server Standalone

You can inspect or test the FastMCP tools using the FastMCP CLI:

fastmcp dev mcp_server.py

💬 Example Prompt Interactions

• "List my upcoming meetings for the week."

• "Check if I am free tomorrow between 2 PM and 5 PM."

• "Schedule a Google Meet with john@example.com tomorrow at 4 PM for 45 minutes titled 'Q3 Sprint Planning'."

• "Reschedule meeting ID abc123xyz to Friday 11 AM."

• "Cancel meeting abc123xyz."