A few days ago, I got a little frustrated that ChatGPT couldn’t access my iCloud calendars. I wanted to ask about my week or add an event from a conversation, so I decided to build a plugin myself.
When I published it on GitHub, the timing turned out to be rather funny: several hours later, on the very same day, OpenAI released its own iCloud Calendar plugin. :) :)
The project now supports both iCloud Calendars and iCloud Reminders, exposed as two separate plugins sharing one backend on the Mac.
Calendar support includes finding, creating and editing events, multiple alerts, and supported changes to recurring events. Reminders support covers creating, editing, completing, reopening and deleting nonrecurring reminders. It uses Apple’s native EventKit access to the accounts already configured in macOS.
I also added an audit trail, configurable limits on bulk modifications and deletions, and retained history with recovery for supported changes. Recovery has provider-specific limits, especially for recurring events; these are documented in the repository.
The practical requirement is an always-on Mac. The MCP server and OpenAI tunnel client run under the calendar owner’s logged-in macOS account. To keep the integration available all the time, that Mac needs to stay awake, online and logged in. I run mine on a Mac Studio.
Once configured in ChatGPT or Code client, you can use it from other devices, including your phone. The private tunnel makes an outbound connection, so there is no need to expose the backend’s ports to the public internet.
This is a personal, single-user integration. The source, quick-install guide and limitations are on GitHub:
