Connecting Google Calendar to OpenClaw

OpenClaw is an open-source AI assistant platform built by FullVibeAI. It runs locally, connects to MCP servers, and supports HTTP MCP transport out of the box. Adding CalendarMCP takes about two minutes.

Before you start

You need:

• OpenClaw installed and running (see openclaw.ai for setup)
• A CalendarMCP API key from calendarmcp.ai (free to start, two-minute Google OAuth flow)

Add CalendarMCP as a plugin

OpenClaw manages MCP integrations as plugins in its config. Open your OpenClaw config file. On macOS it lives at ~/.openclaw/openclaw.json.

Find the plugins array (or create it) and add the CalendarMCP entry:

{
  "plugins": [
    {
      "name": "calendar",
      "transport": "http",
      "url": "https://calendarmcp.ai/api/mcp",
      "headers": {
        "Authorization": "Bearer cmcp_your_api_key_here"
      }
    }
  ]
}

Replace cmcp_your_api_key_here with your key. Save and restart OpenClaw (or use the openclaw gateway restart command if you are running the gateway separately).

Verify the tools are registered

In OpenClaw's chat interface, ask: "What calendar tools do you have?"

You should see the full list: list_events, create_event, update_event, delete_event, find_free_time, batch_update, and more. Ten tools total.

Then try a real prompt: "What do I have on my calendar tomorrow?" OpenClaw will call list_events and return your events in the chat.

Why HTTP MCP matters here

Most older MCP servers run over stdio, which means they spawn a local process and communicate over stdin/stdout. That works fine for Claude Desktop but breaks for web-based and gateway-based agents like OpenClaw.

CalendarMCP runs over HTTP MCP transport, which is what OpenClaw expects for remote tools. You point it at a URL, pass a header, and it works. No local process, no binary to keep updated, no OAuth setup in your Google Cloud Console.

What you can do with it

Once CalendarMCP is wired into OpenClaw, the agent can use your calendar as context in any conversation:

• Morning briefings that pull today's schedule before summarizing email.
• Conflict detection when you ask it to schedule something.
• Batch-blocking focus time for a project sprint.
• Finding free slots across two Google accounts with a single prompt.

OpenClaw's heartbeat system pairs especially well with CalendarMCP. You can configure a periodic check that looks at upcoming events and surfaces reminders or conflicts without you asking.

Multiple Google accounts

CalendarMCP supports connecting multiple Google accounts under one API key. Once you connect a second account at calendarmcp.ai, your OpenClaw agent can query or write to any of them. The prompt looks the same from the agent's perspective. You specify which account or calendar in plain language and CalendarMCP routes it.

This is the main reason to use a hosted MCP server over a self-hosted stdio one. Local setups tie you to one OAuth token at a time. HTTP transport plus a hosted backend gives you a consistent interface regardless of how many accounts you manage.

Troubleshooting

Tools not appearing after restart: Check the config JSON is valid (no trailing commas, no syntax errors). Run openclaw gateway status to see if the plugin registered.

401 errors: The API key is wrong or has leading/trailing whitespace from a paste. Regenerate from the CalendarMCP dashboard and re-paste carefully.

Events from the wrong account: If you have multiple Google accounts connected, tell the agent explicitly which one: "Check my work calendar at work@example.com for next week."

Set it up at calendarmcp.ai. Get the API key, drop it in the config, and your OpenClaw agent has full calendar access in the next restart.