CalendarMCP MCP Server

Content

CalendarMCP is a hosted Model Context Protocol server for Google Calendar. It lets MCP-compatible clients read and write calendar data through a remote HTTP endpoint after the user connects Google Calendar and creates a CalendarMCP API key.

The production endpoint is:

https://calendarmcp.ai/api/mcp

The public repository contains documentation, manifests, and client examples. The hosted CalendarMCP service is not open source.

Source Review

• https://github.com/Full-Vibe/calendarmcp-public
• https://calendarmcp.ai/docs
• https://calendarmcp.ai/api/docs
• https://modelcontextprotocol.io/registry/about
• https://code.claude.com/docs/en/mcp

These sources were reviewed on 2026-06-05. Prefer the live CalendarMCP docs over model memory for endpoint behavior, auth headers, tool names, rate limits, pricing, and client configuration.

Features

• Hosted HTTP MCP endpoint for Google Calendar.
• API-key authentication using an Authorization: Bearer ... header.
• Google account connection through the CalendarMCP dashboard.
• Per-calendar read/write controls enforced server-side.
• Multi-account support under one API key.
• Event listing, creation, update, deletion, and natural-language quick add.
• Free/busy lookup before creating events.
• Attendee management for existing events.
• Batch event updates for up to 50 events in one concurrent call.
• Google Advanced Protection support through service-account sharing, according to the CalendarMCP docs.

Tools

• list_events: list events across one or all connected calendars in a time range.
• get_event: retrieve full details for one event.
• create_event: create an event with attendees, location, reminders, recurrence, or all-day settings.
• update_event: partially update an existing event.
• delete_event: delete an event.
• quick_add_event: create an event from natural language.
• list_calendars: list calendars visible to the API key with read/write permissions.
• find_free_time: query free/busy availability across calendars.
• manage_attendees: add or remove attendees from an event.
• batch_update_events: update up to 50 events in one concurrent call.

Installation

1. Sign in at https://calendarmcp.ai.
2. Connect the Google account or calendars the assistant may access.
3. Copy an API key from the CalendarMCP dashboard.
4. Add the MCP server to the target client using HTTP transport and a bearer auth header.

Claude Code

claude mcp add calendar https://calendarmcp.ai/api/mcp \
  --transport http \
  --header "Authorization: Bearer YOUR_CALENDARMCP_API_KEY"

Cursor or Generic Remote HTTP Client

{
  "mcpServers": {
    "calendar": {
      "url": "https://calendarmcp.ai/api/mcp",
      "headers": {
        "Authorization": "Bearer YOUR_CALENDARMCP_API_KEY"
      }
    }
  }
}

Claude Desktop Through server-fetch

CalendarMCP also documents a Claude Desktop configuration using @modelcontextprotocol/server-fetch:

{
  "mcpServers": {
    "calendar": {
      "command": "npx",
      "args": [
        "@modelcontextprotocol/server-fetch",
        "https://calendarmcp.ai/api/mcp"
      ],
      "env": {
        "MCP_AUTH_HEADER": "Authorization: Bearer YOUR_CALENDARMCP_API_KEY"
      }
    }
  }
}

Access Model

CalendarMCP API keys are issued from the dashboard. One key can include multiple connected Google accounts, and per-calendar read/write permissions are enforced server-side.

Before sharing a config with an assistant, inspect the calendars attached to the key and remove write access for calendars that should remain read-only. Create separate keys for separate agents when their calendar access should differ.

Safe Usage

• Start by asking the assistant to call list_calendars and summarize what it can read or write.
• Use read-only access for agenda summaries, daily planning, or availability checks.
• Use find_free_time before asking the assistant to create meetings.
• Require confirmation before inviting attendees, moving recurring meetings, deleting events, or running batch updates.
• Keep work, personal, executive, HR, legal, and customer calendars separated unless there is a clear approval path for combined access.

Troubleshooting

The client cannot authenticate

Check that the Authorization header uses Bearer YOUR_CALENDARMCP_API_KEY and that the key is active in the CalendarMCP dashboard.

The assistant cannot see an expected calendar

Confirm the calendar is connected to the CalendarMCP account and that the API key has read access to that calendar.

Event writes fail

Check the per-calendar read/write matrix. A key with read access can list events but cannot create, update, delete, or batch-edit them.

The assistant edits too many events

Pause the workflow, inspect the target event IDs and filters, and split broad changes into smaller batches. Treat recurring-event edits and batch_update_events as high-risk operations.