Mjucius Cozi MCP

What mjucius-cozi_mcp does

Cozi Family Organizer exposes calendars, family members, shopping lists, and to-do lists through MCP. The server can inspect appointments by month or search Cozi's calendar across months, then create, update, or delete appointments when write access is enabled. It also supports list and item operations, including creating or renaming lists, adding items, marking items complete, and removing items.

Calendar results include details such as dates, times, attendees, locations, notes, reminders, recurrence information, and whether an entry is read-only. Family-member IDs can be retrieved before creating or updating appointment attendees.

How it works

Each user runs an instance connected to their own Cozi account. The local MCPB and npx modes send credentials to Cozi's API at https://rest.cozi.com; credentials are not sent to the project author. The Cloudflare option stores the account session and password within the user's own Cloudflare setup and is intended for Claude access across web, phone, and desktop.

The default tool surface is read-write. Setting COZI_READ_ONLY=true exposes only family_members, get_lists, get_list_items, get_calendar, search_calendar, and today.

For natural-language dates, call today before converting terms such as “tomorrow” into ISO dates when no other Cozi tool has been called. Recurring appointments require an explicit scope when updated or deleted. Updating both an item's text and completion state uses separate requests rather than one atomic operation.

Setup and configuration

For Claude Desktop, download the latest MCPB from the project's releases and install it. This path does not require Node, npm, or Python, and prompts for the Cozi username and password.

For other MCP clients, configure an npx server using the @mjucius/cozi-mcp package:

{
  "mcpServers": {
    "cozi": {
      "command": "npx",
      "args": ["-y", "@mjucius/cozi-mcp"],
      "env": {
        "COZI_USERNAME": "you@example.com",
        "COZI_PASSWORD": "your-password"
      }
    }
  }
}

The npx method requires Node.js 20 or newer and downloads the package on first use. Credentials are read when the process starts, so restart the MCP client after changing them. A Cloudflare deployment follows a separate setup guide and works with Claude only.

Tools and capabilities

• Inspect family members for appointment attendee IDs.
• Summarize shopping and to-do lists, then retrieve their items.
• Create, rename, and delete lists.
• Add, update, and remove list items.
• Read one month of calendar entries or search appointments across months.
• Create all-day, timed, multi-day, and repeating appointments.
• Partially update appointments while preserving fields not supplied.
• Delete individual occurrences, future occurrences, or full recurring series.
• Retrieve the local machine's date, weekday, time, and timezone.

Limitations and notes

Cozi does not provide OAuth; authentication uses a username and password. Holidays, subscribed-calendar entries, and birthdays are read-only and cannot be changed or deleted. Deleting a complete recurring series should be confirmed with the user before execution.

Calendar deletion and updates require the appointment to be available on the relevant year-and-month page. A newly created appointment may not appear in Cozi search immediately. Cozi authentication also applies exponential backoff after five consecutive failed logins.

The project is unofficial and MIT licensed. Its single-user design means access is based on the local process or the configured Cloudflare instance and the associated Cozi credentials.