io.github.cyanheads/macos-mcp-server

macOS-only. This server controls the local macOS system — it requires the host machine to be running macOS. HTTP transport is supported for completeness, but the practical use case is stdio: run it locally and point your MCP client at it.

---

Overview

macOS system control — application lifecycle, window management, audio and display routing, screenshots, Finder integration, notifications, and Focus mode. Launch, quit, and arrange apps and windows, switch audio devices, capture screenshots, and toggle Focus mode from any MCP client. Runs as a stdio process or a local Streamable HTTP server.

Tools

Tool	Description
macos_get_info	System snapshot: battery level and charging status, power source, Wi-Fi SSID, hostname, macOS version, uptime, and display count
macos_check_permissions	Reports Accessibility, Screen Recording, Automation > Finder, and Notification permission status for the calling process
macos_manage_apps	List running apps, get the frontmost app, launch, quit, force-quit, hide, or show applications
macos_manage_windows	List, focus, move, resize, move_resize, minimize, fullscreen, or close windows across all visible apps
macos_control_volume	Get or set system output volume (0–100) and mute state
macos_control_audio	List audio devices, get current defaults, or switch the default input/output device
macos_control_appearance	Get or set dark/light mode
macos_control_system	Lock the screen or put the display to sleep
macos_take_screenshot	Capture full screen, display, named app window, or pixel region; saves PNG, optional base64 JPEG preview
macos_manage_displays	List connected displays and apply named display layout presets
macos_send_notification	Post a notification to macOS Notification Center
macos_manage_focus	Get or set Do Not Disturb / Focus mode
macos_manage_finder	Frontmost path, current selection, reveal, open with app, or move to Trash

Resources

Resource	Description
macos://system/info	Current macOS system snapshot: battery, power source, Wi-Fi SSID, hostname, version, uptime, display count
macos://audio/devices	All audio input and output devices, including which is the current default. Requires SwitchAudioSource CLI.
macos://displays	Connected display inventory including persistent IDs, type, resolution, origin, rotation, scaling, and enabled state. Requires displayplacer CLI.

Resource data is also accessible via macos_get_info, macos_control_audio (action=list), and macos_manage_displays (action=list).

Capability reference

macos_get_info _tool

• Battery level (0–100), charging state, and power source (AC, Battery, UPS); null on desktops with no battery
• Wi-Fi connection status and SSID
• Hostname, macOS version string (e.g. "15.1.0"), uptime in seconds
• Connected display count
• No permissions required

---

macos_check_permissions _tool

• Reports Accessibility (window manipulation, app hide/show), Screen Recording (window screenshots), Automation > Finder (Finder selection), and Notifications (always granted — osascript bypasses Do Not Disturb)
• Returns the calling process name (e.g. "ghostty", "node") so you know which process to grant permissions for
• Read-only — checks status without triggering an OS permission prompt
• Run this first when debugging why another tool is failing

---

macos_manage_apps _tool

• list — running user-facing apps with name, bundle ID, PID, visible, and frontmost flags
• frontmost — name, bundle ID, PID, and frontmost window title of the active app
• launch — open or activate by app_name or bundle_id; hidden=true starts in the background
• quit (graceful AppleScript quit) vs. force_quit (SIGKILL, no save prompt)
• hide / show — toggle visibility; requires Accessibility
• Typed errors: app_not_found, not_running, accessibility_required

---

macos_manage_windows _tool

• list — all visible windows across apps, with position, size, minimized state, and 0-based display_index
• focus, move, resize, move_resize, minimize, fullscreen, close — target by app_name or exact window_title (title takes precedence when both are given)
• list and focus require no permissions; every other action requires Accessibility
• Typed errors: window_not_found, accessibility_required

---

macos_control_volume _tool

• get — current output volume (0–100) and mute state
• set — accepts level (0–100), muted, or both; level=0 does not mute
• Always returns current state after a set

---

macos_control_audio _tool

• list — all input/output devices with an is_default flag; filter with type
• current — default input and output device names
• switch_output / switch_input — case-insensitive partial name match ("MacBook" matches "MacBook Pro Microphone")
• Volume level is separate (macos_control_volume)
• Requires SwitchAudioSource CLI (brew install switchaudio-osx); typed errors device_not_found, switchaudio_unavailable

---

macos_control_appearance _tool

• get — returns dark_mode: true/false
• set with mode: "dark" | "light" | "toggle" — dark/light are idempotent, toggle flips on each call

---

macos_control_system _tool

• lock — ⌃⌘Q via Accessibility; falls back to the ScreenSaverEngine binary when Accessibility isn't granted
• sleep_display — pmset displaysleepnow; no permissions required
• Both operations are immediate and reversible with any input (wake/unlock)

---

macos_take_screenshot _tool

• target: screen, display (0-based display_index), region (pixel rect) — no Screen Recording required; window (by app_name) requires Screen Recording
• Always saves a full-resolution PNG; path defaults to MACOS_SCREENSHOT_DIR/<timestamp>.png, falling back to ~/Desktop; a custom path must be within ~/Desktop, /tmp, or the home directory
• include_data=true adds a base64 JPEG preview (max 1024px wide, ~70% quality) plus preview_width/preview_height
• Typed errors: screen_recording_required, window_not_found, display_not_found, path_not_writable

---

macos_manage_displays _tool

• list — persistent ID, connection type, resolution, refresh rate, origin, rotation, scaling, and enabled state, plus current_config (a displayplacer command that reproduces the active arrangement)
• apply_layout — activates a named preset from MACOS_DISPLAY_LAYOUTS; raw displayplacer args are never accepted from the caller
• Requires displayplacer CLI (brew install jakehilborn/jakehilborn/displayplacer); typed errors displayplacer_not_found, layout_not_found

---

macos_send_notification _tool

• title required; body, subtitle, and sound=true (default notification sound) are optional
• Each call creates a new notification — not idempotent
• Bypasses Do Not Disturb; no permission required

---

macos_manage_focus _tool

• get — best-effort; reads the Focus assertion database when accessible, returns status: "active" | "inactive" | "unknown"; unknown is expected on macOS 13+ where the database is SIP-protected
• set — requires the built-in "Set Focus" shortcut in Shortcuts.app (present by default on macOS 12+); mode must exactly match a configured Focus profile (e.g. "Do Not Disturb", "Work"); enabled defaults to true
• Typed errors: shortcuts_unavailable, focus_not_found

---

macos_manage_finder _tool

• frontmost_path — POSIX path of the active Finder window, or null when none is open; no permissions required
• get_selection — POSIX paths of selected items; requires Automation > Finder permission
• reveal (open -R), open_with (open -a <App>), trash (moves to Trash — recoverable, not permanent delete)
• Typed errors: finder_not_open, path_not_found, accessibility_required

---

macos://system/info _resource

• Current macOS system snapshot as application/json — battery, power source, Wi-Fi SSID, hostname, version, uptime, display count
• Same data is also reachable via macos_get_info

---

macos://audio/devices _resource

• All audio input and output devices, including which is the current default, as application/json
• Requires SwitchAudioSource CLI
• Same data is also reachable via macos_control_audio (action=list)

---

macos://displays _resource

• Connected display inventory — persistent IDs, type, resolution, origin, rotation, scaling, enabled state, plus current_config — as application/json
• Requires displayplacer CLI
• Same data is also reachable via macos_manage_displays (action=list)

Features

Built on @cyanheads/mcp-ts-core: stdio and Streamable HTTP transports, pluggable auth (none / jwt / oauth), swappable storage (in-memory, filesystem, Supabase, Cloudflare KV/R2/D1), structured logging with optional OpenTelemetry tracing.

macOS-specific:

• osascript service wraps both JXA (runJxa) and AppleScript (runAppleScript) with a configurable timeout
• SwitchAudioSource and displayplacer integrations are optional dependencies — the affected tools fail with ServiceUnavailable and an install instruction when the CLI is absent
• screencapture + sips pipeline for full-resolution PNG capture and downscaled JPEG preview generation
• system_profiler, pmset, and networksetup for hardware, battery, and Wi-Fi state
• Permission-first design — macos_check_permissions reports exactly which process needs which grant before a tool hits Forbidden

Agent-friendly output:

• Permission errors carry specific grant instructions (System Settings > Privacy & Security > [permission type])
• Optional CLI dependencies surface ServiceUnavailable with the exact brew install command needed
• macos_manage_windows action=list reports display_index on every window so agents can reason about multi-monitor layouts
• macos_take_screenshot separates the full-resolution disk write from an optional base64 preview, keeping response size manageable

Getting started

This server is local-only — it controls the macOS system it runs on. Use STDIO transport with your MCP client.

Add the following to your MCP client configuration file:

{
  "mcpServers": {
    "macos-mcp-server": {
      "type": "stdio",
      "command": "bunx",
      "args": ["@cyanheads/macos-mcp-server@latest"],
      "env": {
        "MCP_TRANSPORT_TYPE": "stdio",
        "MCP_LOG_LEVEL": "info"
      }
    }
  }
}

Or with npx (no Bun required):

{
  "mcpServers": {
    "macos-mcp-server": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@cyanheads/macos-mcp-server@latest"],
      "env": {
        "MCP_TRANSPORT_TYPE": "stdio",
        "MCP_LOG_LEVEL": "info"
      }
    }
  }
}

For Streamable HTTP, set the transport and start the server:

MCP_TRANSPORT_TYPE=http MCP_HTTP_PORT=3010 bun run start:http
# Server listens at http://localhost:3010/mcp

Prerequisites

• macOS 12 (Monterey) or higher.
• Bun v1.4.0 or higher (or Node.js v24+).
• Optional: SwitchAudioSource for audio routing (brew install switchaudio-osx).
• Optional: displayplacer for display management (brew install jakehilborn/jakehilborn/displayplacer).

Some tools require macOS permissions granted to the terminal or MCP host app:

Permission	Required by
Accessibility	macos_manage_windows (mutating actions), macos_manage_apps (hide/show), macos_control_system (lock)
Screen Recording	macos_take_screenshot with target=window
Automation > Finder	macos_manage_finder with action=get_selection

Use macos_check_permissions to check current status before running permission-gated operations.

Installation

1. Clone the repository:

git clone https://github.com/cyanheads/macos-mcp-server.git

2. Navigate into the directory:

cd macos-mcp-server

3. Install dependencies:

bun install

4. Configure environment:

cp .env.example .env
# edit .env if you want to set MACOS_SCREENSHOT_DIR or MACOS_DISPLAY_LAYOUTS

Configuration

Variable	Description	Default
MACOS_SCREENSHOT_DIR	Default directory for screenshot files.	~/Desktop
MACOS_DISPLAY_LAYOUTS	JSON object mapping layout names to displayplacer argument strings. Used by macos_manage_displays action=apply_layout.	{}
MCP_TRANSPORT_TYPE	Transport: stdio or http.	stdio
MCP_HTTP_PORT	Port for HTTP server.	3010
MCP_AUTH_MODE	Auth mode: none, jwt, or oauth.	none
MCP_LOG_LEVEL	Log level.	info
MCP_SESSION_MODE	Session storage: auto, stateful, or stateless (HTTP only). This server holds no per-session state, so .env.example sets stateless explicitly.	auto (.env.example sets stateless)
OTEL_ENABLED	Enable OpenTelemetry instrumentation.	false

See .env.example for the full list of optional overrides.

Display layout example:

# Get the current displayplacer command for your setup:
displayplacer list

# Then configure named layouts in your env:
MACOS_DISPLAY_LAYOUTS='{"office":"id:1234 res:2560x1440 hz:60 color_depth:8 scaling:on origin:(0,0) degree:0 id:5678 res:1920x1080 hz:60 color_depth:8 scaling:on origin:(2560,0) degree:0"}'

Running the server

Local development

# One-time build
bun run rebuild

# Run the built server
bun run start:stdio

# Run checks
bun run devcheck   # Lint, format, typecheck, security, changelog sync
bun run test       # Vitest test suite
bun run lint:mcp   # Validate MCP definitions against spec

Project structure

Directory	Purpose
src/index.ts	createApp() entry — registers tools/resources and inits services
src/config/server-config.ts	MACOS_SCREENSHOT_DIR and MACOS_DISPLAY_LAYOUTS env parsing
src/mcp-server/tools/definitions/	13 tool definitions (macos-*.tool.ts)
src/mcp-server/resources/definitions/	3 resource definitions (macos-*.resource.ts)
src/services/osascript/	osascript JXA + AppleScript runner with configurable timeout
src/services/audio/	SwitchAudioSource device listing and switching
src/services/display/	displayplacer list and apply-layout
src/services/screencapture/	screencapture + sips PNG capture and JPEG preview
src/services/system-info/	Battery, Wi-Fi, hostname, uptime via system_profiler/pmset
tests/tools/	Tool tests mirroring definitions

Development guide

See CLAUDE.md for development guidelines and architectural rules. The short version:

• Handlers throw, framework catches — no try/catch in tool logic
• Use ctx.log for request-scoped logging; no console calls
• Read actual system/CLI state and never fabricate it — return null or unknown when the OS can't answer (e.g. battery on desktops, Focus status under SIP protection) rather than guessing
• Services are singletons initialized in createApp() and accessed via get*Service() accessors

Contributing

Issues are welcome. Run checks and tests before submitting:

bun run devcheck
bun run test

License

Apache-2.0 — see LICENSE for details.