create-macos-app

name	create-macos-app
description	Blueprint for setting up a new macOS Xcode project the right way. Use this skill whenever the user asks to create a macOS app, set up a new macOS Xcode project, or bootstrap a macOS application. Covers project creation, scheme configuration, code-level bootstrapping, menu bar setup, build configurations, and linting tooling.

macOS App Setup Blueprint

Walk through each step in order. Some steps are optional — call those out explicitly so the user can decide. When the user already has a partially set up project, ask where they are and pick up from there.

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Step 1 — Create the Xcode Project

In Xcode: File → New → Project → macOS → App.

Fill in product name, bundle ID, team, etc.

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Step 2 — Remove the Storyboard / NIB (Optional)

If the user wants code-only UI (no storyboard or NIB):

1. Delete Main.storyboard or MainMenu.xib from the project (move to Trash).
2. Open Info.plist and remove the corresponding key:
   • For storyboard: NSMainStoryboardFile
   • For NIB: NSMainNibFile

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Step 3 — Configure the Scheme

Open Product → Scheme → Edit Scheme (or ⌘<), select the Run action.

Arguments tab — Add launch argument:

-NSConstraintBasedLayoutVisualizeMutuallyExclusiveConstraints YES

This makes Auto Layout conflicts visible immediately at runtime instead of silently breaking.

Environment Variables tab — Add:

Name	Value
OS_ACTIVITY_MODE	disabled

This suppresses the flood of verbose OS/network log noise in the Xcode console.

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Step 4 — Bootstrap with main.swift

Create a new Swift file named main.swift (the name matters — it marks the entry point).

Add this code:

import Cocoa

let app = NSApplication.shared

if NSClassFromString("XCTestCase") == nil {
    let appDelegate = AppDelegate()
    app.delegate = appDelegate
    _ = NSApplicationMain(CommandLine.argc, CommandLine.unsafeArgv)
} else {
    app.run()
}

Why: When running unit tests, Xcode injects XCTestCase into the process. By detecting this and skipping AppDelegate initialization, tests start faster and avoid side effects from app startup code.

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Step 5 — Remove @main from AppDelegate

Open AppDelegate.swift and remove the @main attribute from the class declaration.

// Before
@main
class AppDelegate: NSObject, NSApplicationDelegate { ... }

// After
class AppDelegate: NSObject, NSApplicationDelegate { ... }

@main was the old entry point; main.swift now owns that role.

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Step 6 — Set Up the Menu Bar

In AppDelegate.applicationDidFinishLaunching, build an NSMenu and assign it:

func applicationDidFinishLaunching(_ notification: Notification) {
    let mainMenu = NSMenu()
    // Build your menu items here...
    NSApplication.shared.mainMenu = mainMenu
}

At minimum you'll want an application menu (with Quit, Hide, etc.) and whatever top-level menus the app needs (File, Edit, Window, Help, etc.).

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Step 7 — Add a PROFILE Build Configuration

This gives you a named configuration for profiling (Instruments) that's separate from Debug and Release.

1. Go to the project settings → Info tab → Configurations.
2. Click + → Duplicate "Release" Configuration → name it PROFILE.

Then in Build Settings, filter by PROFILE and customize as needed (e.g., same optimizations as Release, but with debug symbols for Instruments).

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Step 8 — Separate Bundle ID and Name for Debug and Profile

This lets you install Debug, Profile, and Release builds side-by-side on the same machine.

In Build Settings, set per-configuration overrides:

Setting	DEBUG	PROFILE
PRODUCT_BUNDLE_IDENTIFIER	com.example.MyApp.debug	com.example.MyApp.profile
PRODUCT_NAME	MyApp Debug	MyApp Profile

(Leave Release as the canonical values.)

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Step 9 — Add SwiftLint

1. Add a Run Script Phase: In the target's Build Phases tab, click + → New Run Script Phase. Drag it to run after "Compile Sources". Add the script:

   if which swiftlint > /dev/null; then
     swiftlint
   else
     echo "warning: SwiftLint not installed, download from https://github.com/realm/SwiftLint"
   fi
   

2. Disable User Script Sandboxing: In Build Settings, search for ENABLE_USER_SCRIPT_SANDBOXING and set it to No. This is required for SwiftLint to read source files from the project directory.

3. Add a .swiftlint.yml at the project root to configure rules.

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Step 10 — Add SwiftFormat

Similar to SwiftLint, add another Run Script Phase (after SwiftLint):

if which swiftformat > /dev/null; then
  swiftformat .
else
  echo "warning: SwiftFormat not installed, download from https://github.com/nicklockwood/SwiftFormat"
fi

Add a .swiftformat config file at the project root to set your formatting rules.

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Checklist

When done, confirm with the user:

• Project created
• Storyboard/NIB removed (if wanted)
• Scheme configured (launch args + env vars)
• main.swift created, @main removed from AppDelegate
• Menu bar wired up
• PROFILE build configuration added
• Debug + Profile bundle IDs / names set
• SwiftLint run script + sandboxing disabled
• SwiftFormat run script added