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

Resources

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

Related MCP server: mcp-server-macos-use

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

• quit, force_quit, hide, and show first check that the app is running — resolved by application name the way tell application does ("Visual Studio Code" finds the Code process), without launching it — and return not_running when it isn't

• Typed errors: app_not_found (launch of an app that isn't installed), no_frontmost_app, 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)

• move needs x/y, resize needs width/height (both greater than 0), move_resize needs all four

• 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 — requires level (0–100), muted, or both; level=0 does not mute

• Always returns current state, with the action echoed

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, with the action echoed

• set requires mode: "dark" | "light" | "toggle" — dark/light are idempotent, toggle flips on each call

• Scripts System Events; typed error accessibility_required when Automation > System Events is denied

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 integer display_index, default 0), region (pixel rect, width/height greater than 0) — 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

• get_selection — POSIX paths of selected items

• reveal (open -R), open_with (open -a <App>, or the default app when app_name is omitted), trash (moves to Trash — recoverable, never a permanent delete)

• open_with and trash check that the path exists before calling open or Finder

• frontmost_path, get_selection, and trash script Finder and require Automation > Finder permission; reveal and open_with need none

• Typed errors: finder_not_open, path_not_found, app_not_found (unknown open_with app), trash_refused (Finder declined an existing item — locked, in use, or no Trash on the volume), 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 the accessibility_required reason and grant instructions for the permission actually denied — Privacy & Security > Accessibility, or Privacy & Security > Automation for the named app

• A missing per-action argument (set without mode, quit without app_name) is rejected before anything runs, as -32602 with reason invalid_arguments and a hint naming what to send; each multi-action tool advertises those requirements in its inputSchema

• Errors carry the failing program's own error text, never its command line or script source

• 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:

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

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

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.