docs/mcp/google_tools_mcp.md

Google Calendar and GMail Tools / MCP

1) Base setup

1.1) GMail Account

1.2) Google Cloud

Terraform Modifications (Minimal)

You can extend your existing Gmail Terraform to include Calendar support. Add these to your main.tf:

# Enable the Google Calendar API
resource "google_project_service" "calendar_api" {
  project = google_project.project.project_id
  service = "calendar.googleapis.com"
  disable_on_destroy = false
}

And if you want, you can add an output for convenience:

output "console_calendar_api_url" {
  value = "https://console.cloud.google.com/apis/library/calendar.googleapis.com?project=${google_project.project.project_id}"
}

After adding, re-run your scripts:

cd terraform
terraform apply

This enables the Calendar API in the same project your Gmail MCP is using — so you don't have to create a second one.

Terraform will:

1. Detect that you already have a project and Gmail API from before.
2. Notice the new Calendar API resource in ``main.tf.
3. Apply only that new change (plus any small diff in IAM roles if needed).

💡 What Happens Internally When you run terraform apply, Terraform will:

• Read your current state file (terraform.tfstate).
• Query GCP to check what's already deployed.
• Compute a plan (the difference between your state and the .tf files).

🔑 OAuth Setup — Shared Consent Screen

You do not need a new consent screen — just reuse your existing one (Gmail MCP Local) and add the Calendar scope.

Go to: 👉 [Google Cloud Console → APIs & Services → OAuth consent screen → Edit app → Data access → Add scopes] Add this scope:

https://www.googleapis.com/auth/calendar

You'll now have Gmail + Calendar under one consent. Then, create a second OAuth client: Application type: Desktop app Name: calendar-mcp-desktop Download the credentials JSON → save it to:

~/.calendar-mcp/credentials.json

The Calendar MCP server will then use this credentials file when it first authenticates.

🧩 MCP Client Config (Claude or LangGraph)

Just add a new block alongside your Gmail entry. For Claude Desktop (claude_desktop_config.json)

{
  "mcpServers": {
    "gmail": {
      "command": "uv",
      "args": [
        "--directory",
        "/Users/sebastianwefers/Desktop/development/recruitment-agent-mcp-hackathon-winter25/src/mcp_servers/gmail-mcp",
        "run",
        "gmail",
        "--creds-file-path",
        "/Users/sebastianwefers/.gmail-mcp/credentials.json",
        "--token-path",
        "/Users/sebastianwefers/.gmail-mcp/token.json"
      ]
    },
    "google_calendar": {
      "command": "uv",
      "args": [
        "--directory",
        "/Users/sebastianwefers/Desktop/development/recruitment-agent-mcp-hackathon-winter25/src/mcp_servers/calendar-mcp",
        "run",
        "calendar"
      ]
    }
  }
}

For LangGraph:

client = MultiServerMCPClient({
    "gmail": {
        "command": "uv",
        "args": [
            "--directory", "/Users/sebastianwefers/Desktop/development/recruitment-agent-mcp-hackathon-winter25/src/mcp_servers/gmail-mcp",
            "run", "gmail",
            "--creds-file-path", "/Users/sebastianwefers/.gmail-mcp/credentials.json",
            "--token-path", "/Users/sebastianwefers/.gmail-mcp/token.json"
        ],
        "transport": "stdio"
    },
    "google_calendar": {
        "command": "uv",
        "args": [
            "--directory", "/Users/sebastianwefers/Desktop/development/recruitment-agent-mcp-hackathon-winter25/src/mcp_servers/calendar-mcp",
            "run", "calendar"
        ],
        "transport": "stdio"
    }
})

Environment Variables (.env)

Create the .env in your calendar-mcp repo root, just like described in its README:

GOOGLE_CLIENT_ID='YOUR_CLIENT_ID'
GOOGLE_CLIENT_SECRET='YOUR_CLIENT_SECRET'
TOKEN_FILE_PATH='.gcp-saved-tokens.json'
OAUTH_CALLBACK_PORT=8080
CALENDAR_SCOPES='https://www.googleapis.com/auth/calendar'

⚠️ Make sure the redirect URI matches:

http://localhost:8080/oauth2callback

You'll go through one browser OAuth login on first run, and then .gcp-saved-tokens.json will be created — no need to repeat.

2) Model Context Protocol

References

• Official MCP Docs
• MCP Crash Course by YouTuber & AI Engineer Dave Ebbelaar
• Existing Repo's
  • Curated list of MCP servers hosted by MCP themselves.
  • Goole Calendar
  • calendar repo alterntives:
    • https://github.com/nspady/google-calendar-mcp/tree/main/src/tools

# Calendar MCP (Dual Layer)
LLM Agent
   │
   │  JSON-RPC over STDIO
   ▼
MCP Bridge (mcp_bridge.py)
   │  HTTP requests to localhost:8000
   ▼
FastAPI Server (server.py)
   │
   └── Google Calendar API (OAuth + REST)

• GMail

    # Gmail MCP (Pure MCP)
LLM Agent
   │
   │  JSON-RPC over STDIO
   ▼
Gmail MCP Server
   │
   └── Gmail API (OAuth + REST)

• Gmail
• Gmail

🧱 1️⃣ Compatibility Breakdown

Area	Gmail MCP	Calendar MCP	Compatible?	Notes
Transport	MCP via STDIO	MCP via STDIO (through FastAPI bridge)	✅	Works out of the box with same client setup.
Auth Type	OAuth 2.0 Desktop Client	OAuth 2.0 Desktop Client	✅	Identical flow; can reuse same consent screen + test users.
Scopes	https://www.googleapis.com/auth/gmail.modify	https://www.googleapis.com/auth/calendar	✅	Different scopes, but both can live under one consent screen.
Terraform	Creates project, enables Gmail API, sets roles	Just needs Calendar API enabled too	✅	Add one more API + scope to Terraform config.
Token Storage	~/.gmail-mcp/token.json	.gcp-saved-tokens.json	✅	Each uses its own token file; keep separate to avoid refresh token mix-ups.
Runtime	uv stdio server	python run_server.py (auto-switches to stdio)	✅	You can use uv for both, if you prefer consistency.
MCP Integration	Claude / LangGraph via config	Same	✅	Just add another entry under mcpServers.