Fantastical 4.1.15 Adds Calendar Mirroring
Fantastical 4.1.15 introduces Calendar Mirroring, a privacy-focused feature that lets users connect two separate calendars so events from one automatically appear on another, with the option to show full details or just mark time as "Busy." All event data stays on the device and is not sent to Flexibits servers.
Background
- Fantastical is a premium calendaring app for macOS/iOS made by Flexibits. It is popular in the Apple ecosystem for its polished design and deep integration with multiple calendar services (Google, Microsoft 365, iCloud, etc.).
- "Calendar Mirroring" is a new feature (in version 4.1.15) that copies events from one calendar to another entirely on-device — no data reaches Flexibits' servers. Users can mirror a personal calendar onto a work calendar, for example, and optionally hide event details by showing only "Busy" blocks.
- The article is by John Gruber, author of Daring Fireball, a long-running Apple- and tech-commentary blog. He often writes about software he personally uses or finds noteworthy.
- MCP (Model Context Protocol) is an open standard developed by Anthropic (makers of Claude) that lets AI agents interact with external tools like calendars. Fantastical added MCP support so Claude (and other AI agents that support the standard) can read/write calendar data.
- The "criminally bad" Claude Mac app reference is Gruber's own prior criticism of the official Claude desktop app for macOS, which he considers poorly made compared to ChatGPT's offering.