MCSC — Mission Control Shortcuts

A lightweight, high-performance macOS utility focused on fast window management and keyboard-driven workflows.

MCSC is a small background app built as a learning project to explore low-level macOS APIs, event systems, accessibility automation, and performance-focused desktop tooling.

It is heavily inspired by the original Mission Control Plus app.

“Wouldn’t be possible without the original Mission Control Plus.”

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Why This Exists

Most macOS utilities in this category are either:

• Electron-heavy
• Resource intensive
• Over-engineered
• Closed ecosystems

MCSC was built with a different goal:

• native macOS APIs
• minimal memory usage
• near-zero idle CPU usage
• instant keyboard response
• small and understandable codebase

This project intentionally avoids unnecessary abstraction layers where possible and uses direct AppKit/Core Foundation integration instead of large UI frameworks.

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Features

Global Keyboard Shortcuts

System-wide shortcuts powered by low-level CGEventTap.

Supported actions:

Shortcut	Action
Cmd + W	Close active window
Cmd + Q	Quit active application
Cmd + M	Minimize active window
Cmd + H	Hide active application
Cmd + Space	Trigger Mission Control UI fix

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Trackpad Gestures

Two-finger and pinch gestures, also scoped to Mission Control only:

Gesture	Action
Two-finger swipe up	Hide / minimize active window
Two-finger swipe down	Toggle fullscreen
Two-finger swipe left	Close tab
Two-finger swipe right	Reopen tab
Pinch in	Close window / quit app
Two-finger double tap	Reasonable size / almost maximize

Holding Cmd while gesturing maps to the force-quit / app-level variant of the same action. Each gesture fires once per finger lift — keeping fingers down and repeating the motion will not re-trigger it until you lift and touch again.

Accessibility API Integration

Uses AXUIElement directly to:

• inspect windows
• manipulate application state
• interact with windows from other apps
• manage focus and visibility

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Mission Control Monitoring

All gestures and Cmd shortcuts are scoped to Mission Control only. They fire while Mission Control is open and are deliberately suppressed in:

• Launchpad
• expanded Finder folder stacks in the Dock
• the normal desktop

Detection is performed by inspecting the Dock's window layers via CGWindowListCopyWindowInfo — Mission Control exposes a full-screen Dock overlay at layer 20 together with the Dock bar at layer ≤ 18, whereas Launchpad (layers 27–29) and Finder folder stacks (overlay only, no Dock bar) do not match this signature. The result is cached for 200ms to avoid polling on every trackpad frame.

MCSC can also automatically attempt recovery sequences (Cmd + Space) when macOS gets stuck during Mission Control interactions.

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Launch at Login

Integrated using SMAppService.

The app can automatically start with macOS and remain quietly available in the background.

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Performance Focused

MCSC is designed to stay lightweight at all times.

Typical runtime characteristics:

• ~0% idle CPU usage
• ~14MB memory usage
• negligible battery impact
• event-driven architecture
• no unnecessary polling loops

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Technical Overview

MCSC uses a service-oriented architecture inspired by MVVM principles.

Core Services

• EventTapService

  • global keyboard interception
  • low-level event processing

• AccessibilityService

  • window inspection and manipulation
  • AX API communication

• MissionControlService

  • Mission Control detection via Dock window-layer analysis (CGWindowList)
  • scopes gestures & shortcuts to Mission Control only
  • recovery handling (Cmd + Space fix sequence)

• LaunchAtLoginService

  • startup integration using SMAppService

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Technologies Used

• Swift
• AppKit
• Core Foundation
• Accessibility APIs
• CGEventTap
• SMAppService

The project also experiments with:

• explicit Core Foundation memory management
• Unmanaged<T>
• manual teardown strategies
• low-level macOS event handling

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Installation

Clone the Repository

git clone https://github.com/yourusername/MCSC.git
cd MCSC

Open in Xcode

open MCSC.xcodeproj

Build

Build using the MCSC scheme inside Xcode.

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First Launch

When launching for the first time, macOS will ask for:

Accessibility Permissions

Required for:

• controlling windows
• listening to global shortcuts
• interacting with other applications

Grant access from:

System Settings
→ Privacy & Security
→ Accessibility

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Code Signing

If you use Sentinel for signing:

sentinel sign --app MCSC.app --identity "Developer ID Application: Your Name (TeamID)"

Verify signature:

codesign -dv --verbose=4 MCSC.app

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Performance Notes

Observed during runtime testing on macOS:

Metric	Typical Usage
CPU	~0% idle
Memory	~14MB RSS
Battery Impact	Negligible

The app is intentionally event-driven to avoid unnecessary background activity.

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Learning Project Disclosure

This project exists primarily as an educational exercise.

It was built to better understand:

• macOS internals
• accessibility APIs
• event taps
• Mission Control behavior
• low-level Swift patterns
• background utilities

AI Usage Disclosure

Codex / AI agentic coding tools were used during development.

This project is not presented as fully handcrafted from scratch.

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Important Note

“It is an educational project for me.
Except bugs — if you want something better, pay for the original app.”

Support the original developers if you want a polished production-grade experience.

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Credits

Inspired by:

• Mission Control Plus

Massive respect to the original creators whose work inspired this project.

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License

MIT License