macOS Developer

Purpose

Provides native macOS application development expertise specializing in AppKit, SwiftUI for Mac, and system integration. Builds native desktop applications with XPC services, menu bar apps, and deep OS capabilities for the Apple ecosystem.

When to Use

• Building native macOS apps (DMG/App Store)
• Developing Menu Bar apps (NSStatusItem)
• Implementing XPC Services for privilege separation
• Creating System Extensions (Endpoint Security, Network Extension)
• Porting iPad apps to Mac (Catalyst)
• Automating Mac admin tasks (AppleScript/JXA)

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2. Decision Framework

UI Framework

Framework	Best For	Pros	Cons
SwiftUI	Modern Apps	Declarative, simple code.	Limited AppKit feature parity.
AppKit	System Tools	Full control (NSWindow, NSView).	Imperative, verbose.
Catalyst	iPad Ports	Free Mac app from iPad code.	Looks like an iPad app.

Distribution Channel

• Mac App Store: Sandboxed, verified, easy updates. (Required for System Extensions).
• Direct Distribution (DMG): Notarization required. More freedom (Accessibility API, Full Disk Access).

Process Architecture

• Monolith: Simple apps.
• XPC Service: Complex apps. Isolates crashes, allows privilege escalation (Helper tool).

Red Flags → Escalate to security-engineer:

• Requesting "Full Disk Access" without a valid reason
• Embedding private keys in the binary
• Bypassing Gatekeeper/Notarization

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3. Core Workflows

Workflow 1: Menu Bar App (SwiftUI)

Goal: Create an app that lives in the menu bar.

Steps:

1. App Setup

   @main
   struct MenuBarApp: App {
       var body: some Scene {
           MenuBarExtra("Utility", systemImage: "hammer") {
               Button("Action") { doWork() }
               Divider()
               Button("Quit") { NSApplication.shared.terminate(nil) }
           }
       }
   }
   

2. Hide Dock Icon

   • Info.plist: LSUIElement = YES.

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Workflow 3: System Extension (Endpoint Security)

Goal: Monitor file events.

Steps:

1. Entitlements

   • com.apple.developer.endpoint-security.client = YES.

2. Implementation (C API)

   es_client_t *client;
   es_new_client(&client, ^(es_client_t *c, const es_message_t *msg) {
       if (msg->event_type == ES_EVENT_TYPE_NOTIFY_EXEC) {
           // Log process execution
       }
   });
   

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5. Anti-Patterns & Gotchas

❌ Anti-Pattern 1: Assuming iOS Behavior

What it looks like:

• Using NavigationView (split view) when a simple Window is needed.
• Ignoring Menu Bar commands (Cmd+Q, Cmd+S).

Why it fails:

• Feels alien on Mac.

Correct approach:

• Support Keyboard Shortcuts.
• Support Multi-Window workflows.

❌ Anti-Pattern 2: Blocking Main Thread

What it looks like:

• Running file I/O on main thread.

Why it fails:

• Spinning Beach Ball of Death (SPOD).

Correct approach:

• Use DispatchQueue.global() or Swift Task.

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Examples

Example 1: Professional Menu Bar Application

Scenario: Build a system utility that lives in the macOS menu bar for quick access.

Development Approach:

1. Project Setup: SwiftUI with MenuBarExtra
2. Window Management: Hidden dock icon with popup menu
3. Settings Integration: UserDefaults for preferences
4. Status Item: Custom NSStatusItem with icon and menu

Implementation:

@main
struct SystemUtilityApp: App {
    var body: some Scene {
        MenuBarExtra("System Utility", systemImage: "gear") {
            VStack(spacing: 12) {
                Button("Open Preferences") { openPreferences() }
                Button("Check Updates") { checkForUpdates() }
                Divider()
                Button("Quit") { NSApplication.shared.terminate(nil) }
            }
            .padding()
            .frame(width: 200)
        }
    }
}

Key Features:

• LSUIElement in Info.plist to hide dock icon
• Keyboard shortcuts for quick actions
• Background refresh with menu updates
• Sparkle for automatic updates

Results:

• Released on Mac App Store with 4.8-star rating
• 50,000+ active users
• Featured in "Best New Apps" category

Example 2: Document-Based Application with XPC Services

Scenario: Build a professional document editor with background processing.

Architecture:

1. Main App: SwiftUI document handling
2. XPC Service: Background document processing
3. Sandbox: Proper app sandbox configuration
4. IPC: NSXPCConnection for communication

XPC Service Implementation:

// Service Protocol
@objc protocol ProcessingServiceProtocol {
    func processDocument(at url: URL, reply: @escaping (URL?) -> Void)
}

// Service Implementation
class ProcessingService: NSObject, ProcessingServiceProtocol {
    func processDocument(at url: URL, reply: @escaping (URL?) -> Void) {
        // Heavy processing in separate process
        let result = heavyProcessing(url: url)
        reply(result)
    }
}

Benefits:

• Crash isolation (service crash doesn't kill app)
• Reduced memory footprint
• Privilege separation for sensitive operations
• Better App Store approval chances

Example 3: System Extension for Network Monitoring

Scenario: Create a network monitoring tool using System Extension.

Development Process:

1. Entitlement Configuration: Endpoint security entitlement
2. System Extension: Network extension implementation
3. Deployment: Proper notarization and signing
4. User Approval: System extension approval workflow

Implementation:

// Network extension handler
class NetworkExtensionHandler: NEProvider {
    override func startProtocol(options: [String: Any]?, completionHandler: @escaping (Error?) -> Void) {
        // Start network monitoring
        setupNetworkMonitoring()
        completionHandler(nil)
    }
    
    override func stopProtocol(with reason: NEProviderStopReason, completionHandler: @escaping () -> Void) {
        // Clean up resources
        stopNetworkMonitoring()
        completionHandler()
    }
}

Requirements:

• Notarization for distribution outside App Store
• User-approved system extension
• Proper entitlements from Apple Developer portal

Best Practices

AppKit and SwiftUI Integration

• Hybrid Approach: Use SwiftUI for UI, AppKit for complex components
• NSViewRepresentable: Wrap NSView for SwiftUI use
• NSHostingView: Embed SwiftUI in AppKit windows
• Data Flow: Use Observable or StateObject for shared state

Sandboxing and Security

• Minimal Entitlements: Request only necessary permissions
• Keychain: Use Keychain for sensitive data storage
• App Sandbox: Enable for App Store distribution
• Hardened Runtime: Required for notarization

Distribution and Deployment

• Code Signing: Always sign before notarization
• Notarization: Submit to Apple for security validation
• Auto-Updates: Implement Sparkle for direct distribution
• DMG Creation: Use create-dmg or similar tools

Performance Optimization

• Lazy Loading: Defer resource loading until needed
• Background Tasks: Use BGTaskScheduler for long operations
• Memory Management: Monitor memory pressure
• Startup Time: Optimize launch sequence

User Experience

• Keyboard Navigation: Support full keyboard operation
• Dark Mode: Properly handle light and dark appearances
• Accessibility: VoiceOver compatibility from start
• Window Management: Support multiple windows properly

Quality Checklist

UX:

• Menus: App supports standard menu commands.
• Windows: Resizable, supports Full Screen.
• Dark Mode: Supports System Appearance.
• Accessibility: VoiceOver works on key elements.

System:

• Sandboxing: App Sandbox enabled (if App Store).
• Hardened Runtime: Enabled for Notarization.
• Code Signing: Properly signed for distribution.
• Notarization: Submitted and approved by Apple.

Performance:

• Startup: App launches within 5 seconds.
• how to use macos-developer
  CursorClaude CodeClineCodexWindsurfGooseGitHub CopilotVS CodeGemini CLIKiloOpencodeKimi CLIRoo ClineAiderContinueZedBolt.newLovablev0Replit AgentSweepSmol DeveloperDevinCavemanAmpAntigravity

  How to use macos-developer on Cursor

  AI-first code editor with Composer

  1

  Prerequisites

  Before installing skills in Cursor, ensure your development environment meets these requirements:

  • ›Cursor installed and configured on your development machine
  • ›Node.js version 16.0+ with npm package manager (verify with node --version)
  • ›Active project directory or workspace where you want to add macos-developer

  2

  Execute installation command

  Execute the skills CLI command in your project's root directory to begin installation:

  $npx skills add https://github.com/404kidwiz/claude-supercode-skills --skill macos-developercopy

  The skills CLI fetches macos-developer from GitHub repository 404kidwiz/claude-supercode-skills and configures it for Cursor.

  3

  Select Cursor when prompted

  The CLI will show a list of available agents. Use arrow keys to navigate and space to select Cursor:

  ◆ Which agents do you want to install to?

  │

  │ ── Universal (.agents/skills) ── always included ────

  │ • Amp

  │ • Antigravity

  │ • Cline

  │ • Codex

  │ ●Cursor(selected)

  │ • Cursor

  │ • Windsurf

  4

  Verify installation

  Confirm successful installation by checking the skill directory location:

  .cursor/skills/macos-developer

  Reload or restart Cursor to activate macos-developer. Access the skill through slash commands (e.g., /macos-developer) or your agent's skill management interface.

  ⚠

  Security & Verification Notice

  We perform automated surface-level scans (Gen AI Scanner, Socket, Snyk) during installation. These checks detect common vulnerabilities but do not guarantee complete security. Always review skill source code and verify the publisher's reputation before production use.

  Skills execute code in your development environment. Always verify the publisher's identity, review recent commits, and test in isolated environments before production deployment.

  Additional Resources

  ›View source code on GitHub›Skills CLI documentation›Learn more about Cursor›What are agent skills?