iOS Development Skill

Purpose

Modern iOS development (Swift 6, iOS 18+, SwiftUI, UIKit) with XcodeBuildMCP integration for autonomous Xcode operations.

When Active

User mentions iOS, Swift, SwiftUI, UIKit, iPhone app, iPad app, or iOS-specific commands.

Specialized Sub-Skills

This skill includes 3 specialized sub-skills for different iOS development aspects:

1. Development Patterns

Reference: ios/development/references/development.md

• Swift 6 concurrency (async/await, Sendable, Actors)
• SwiftUI vs UIKit strategy
• Architecture patterns (MVVM, TCA)
• State management (@Observable, property wrappers)
• NavigationStack implementation
• Networking with URLSession
• Persistence (SwiftData, Core Data)
• Common UI components (List, Grid, Sheet, Form)
• Debugging patterns

2. Build & Simulator Management

Reference: ios/development/references/build.md

• Xcode project configuration
• Build settings and schemes
• Swift Package Manager
• Dependency management (SPM, CocoaPods)
• Asset catalogs and resources
• Code signing and provisioning
• Build optimization
• Simulator management (xcrun simctl + XcodeBuildMCP)
• Common build errors and fixes
• MCP tool patterns (discover_projs, list_schemes, build_sim, etc.)

3. Testing Strategies

Reference: ios/development/references/tester.md

• XCTest patterns (unit tests)
• XCUITest patterns (UI tests)
• Mock dependencies setup
• Given-When-Then structure
• Async/await testing
• Coverage goals and reporting
• Test organization
• Accessibility identifiers for UI testing
• MCP test automation (test_sim, test_device)

XcodeBuildMCP Integration

When XcodeBuildMCP is available, this skill provides autonomous Xcode operations:

MCP Capabilities

• Project Discovery: Auto-discover projects and schemes
• Build Automation: Build for simulator, device, or macOS
• Simulator Management: Boot, install, launch, stop apps
• Testing: Run XCTest/XCUITest suites
• UI Automation: Tap, swipe, type, screenshot
• Log Capture: Stream simulator/device logs
• Environment Validation: Run diagnostics

Prerequisites

• macOS 14.5+ with Xcode 16.x+
• XcodeBuildMCP server: claude mcp add XcodeBuildMCP npx xcodebuildmcp@latest

Patterns

@Observable (iOS 17+)

@Observable
class ProductsViewModel {
    var products: [Product] = []
    var isLoading = false

    func loadProducts() async {
        isLoading = true
        defer { isLoading = false }
        products = try await productService.fetch()
    }
}

NavigationStack

enum Route: Hashable {
    case product(Product)
    case settings
}

struct AppView: View {
    @State private var path: [Route] = []

    var body: some View {
        NavigationStack(path: $path) {
            HomeView()
                .navigationDestination(for: Route.self) { route in
                    // route handling
                }
        }
    }
}

Actor for Thread-Safety

actor NetworkManager {
    func fetch(_ url: URL) async throws -> Data {
        // Thread-safe networking
    }
}

MCP Workflow Examples

Build for Simulator

// MCP approach:
mcp__xcodebuildmcp__discover_projs({ workspaceRoot: '.' })
mcp__xcodebuildmcp__list_schemes({ workspacePath: 'MyApp.xcworkspace' })
mcp__xcodebuildmcp__build_sim({
  workspacePath: 'MyApp.xcworkspace',
  scheme: 'MyApp',
  simulatorId: 'iPhone-16-Pro-UUID'
})

Run Tests

mcp__xcodebuildmcp__test_sim({
  projectPath: 'MyApp.xcodeproj',
  scheme: 'MyApp',
  simulatorId: 'UUID'
})

UI Automation

// IMPORTANT: Always use describe_ui first
mcp__xcodebuildmcp__describe_ui({ simulatorId: 'UUID' })
// Then parse UI hierarchy and interact
mcp__xcodebuildmcp__tap({ simulatorId: 'UUID', x: 100, y: 200 })

Tech Stack

• iOS 18+ SDK, Swift 6.0+
• SwiftUI (primary), UIKit (fallback)
• SwiftData for persistence
• XCTest/XCUITest for testing
• XcodeBuildMCP for automation (optional)

Sub-Skill Routing

When this skill is active and user intent matches a sub-skill, delegate:

Rules

• SwiftUI first; UIKit only when required
• Use @Observable, not ObservableObject
• async/await, not completion handlers
• MainActor for all UI updates
• Write tests for business logic
• Build after each major implementation step
• Use Swift Testing framework for new tests (iOS 18+)
• Mock network calls with URLProtocol or dependency injection

Build Commands

# MCP (preferred)
mcp__xcodebuildmcp__build_sim  # Build for simulator
mcp__xcodebuildmcp__test_sim   # Run tests

# Fallback
xcodebuild -project MyApp.xcodeproj -scheme MyApp -sdk iphonesimulator build
xcodebuild test -project MyApp.xcodeproj -scheme MyApp -destination 'platform=iOS Simulator,name=iPhone 15'

Simulator Commands

xcrun simctl list devices          # List devices
xcrun simctl boot "iPhone 15 Pro"  # Boot
xcrun simctl install booted /path/to/MyApp.app  # Install
xcrun simctl launch booted com.example.MyApp    # Launch
xcrun simctl io booted screenshot screenshot.png  # Screenshot
xcrun simctl erase "iPhone 15 Pro"  # Reset