"Proton Calendar" matching MCP connectors:

Contio MeetingOS: meetings, transcripts, action items, agendas, calendar, and project management.

Invite someone to a calendar event by phone number and get their real email back when they accept.

WhatsApp® reminders and rescheduling for Calendly. Public read-only MCP endpoint.

AI agent platform: manage leads, conversations, bots, calendar and CRM via MCP.

A MCP server that works with Outlook Calendar to manage event listing, reading, and updates.