macOS Ecosystem MCP Server

A fast, native Model Context Protocol (MCP) server for Claude that provides direct access to macOS productivity apps: Reminders, Calendar, and Notes.

Why This Rewrite?

The original Node.js/TypeScript server shelled out to osascript for every tool call — adding 300–800 ms of process-startup overhead each time.

This Swift rewrite:

• Uses EventKit natively for Reminders and Calendar (no subprocess)

• Only shells out to osascript for Notes (Notes.framework is private)

• Compiles to a single self-contained binary — no Node.js runtime required

• Speaks the MCP stdio protocol directly via the official Swift SDK

Related MCP server: macos-mcp

Features

🗓️ Reminders (4 tools — EventKit)

• reminders_add — Create reminders with title, notes, due date, priority

• reminders_list — List reminders, filter by list and completion status

• reminders_complete — Mark a reminder as completed (by ID or title)

• reminders_search — Search reminders by keyword

📅 Calendar (5 tools — EventKit)

• calendar_create_event — Create events with location, notes, alerts

• calendar_list_events — List events within a date range

• calendar_find_free_time — Find available time slots

• calendar_update_event — Modify existing events

• calendar_delete_event — Delete events

📝 Notes (3 tools — osascript)

• notes_create — Create notes with title and body (HTML supported)

• notes_append — Append content to existing notes

• notes_search — Search notes by keyword

💬 iMessage (4 tools — SQLite reads + osascript sends)

• imessage_list_chats — List recent conversations with participants and a last-message preview

• imessage_read — Read a conversation by chat_guid or handle; includes attachment paths

• imessage_search — Search message text across all conversations

• imessage_send — Send text and/or a file attachment to an allowlisted contact

Reads query the local ~/Library/Messages/chat.db directly (read-only). Sends go through AppleScript and are gated by a fail-closed contact allowlist — sending is disabled until you configure one:

• Env var: MACOS_MCP_IMESSAGE_ALLOWLIST="+15551234567,friend@example.com"

• And/or file ~/.config/macos-mcp/imessage-allowlist.json:

  { "allow": ["+15551234567", "friend@example.com"] }

Phone numbers are matched loosely (last 10 digits), so formatting/country-code differences still match. Attachments from protected directories (the config dir, ~/Library/Messages) are refused.

Requirements

• macOS 13 Ventura or later

• Xcode 15+ / Swift 5.9+ (build only)

• Reminders, Calendar, Contacts, and Notes access granted in System Settings → Privacy & Security

• Full Disk Access for the app running this server (Terminal, your MCP client, etc.) — required to read chat.db and to send via Messages. Grant it under System Settings → Privacy & Security → Full Disk Access. Without it, the iMessage tools return an actionable error.

Build from Source

git clone https://github.com/neverprepared/macos-ecosystem-mcp.git
cd macos-ecosystem-mcp
swift build -c release

The binary is placed at:

.build/release/macos-mcp

Install it system-wide:

sudo cp .build/release/macos-mcp /usr/local/bin/macos-mcp

macOS Permissions

The first time the binary runs it will request access. You can also grant it in advance:

1. System Settings → Privacy & Security → Reminders — add macos-mcp

2. System Settings → Privacy & Security → Calendars — add macos-mcp

3. System Settings → Privacy & Security → Automation → Notes — add macos-mcp

Claude Desktop Configuration

Add this to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "macos-ecosystem": {
      "command": "/usr/local/bin/macos-mcp"
    }
  }
}

Or using the local build path:

{
  "mcpServers": {
    "macos-ecosystem": {
      "command": "/path/to/macos-ecosystem-mcp/.build/release/macos-mcp"
    }
  }
}

Restart Claude Desktop after editing the config.

Tool Reference

reminders_add

reminders_list

reminders_complete

reminders_search

calendar_create_event

calendar_list_events

calendar_find_free_time

calendar_update_event

calendar_delete_event

notes_create

notes_append

notes_search

Architecture

Sources/macos-mcp/
├── App.swift              # @main entry — MCP server setup and tool dispatcher
├── ToolDefinitions.swift  # JSON Schema definitions for all 12 tools
├── EventKitManager.swift  # Swift actor wrapping EKEventStore (reminders + calendar)
└── NotesHandler.swift     # osascript runner for Notes operations

Notes on Flagged Reminders

EventKit does not expose the "flagged" status of reminders (it is a Reminders-app-specific attribute not in the EventKit API). The flagged parameter is accepted but silently ignored when creating reminders.

License

MIT