/error-monitoring

name: error-monitoring
description: Generates protocol-based error/crash monitoring with swappable providers (Sentry, Crashlytics). Use when user wants to add crash reporting, error tracking, or production monitoring.
allowed-tools: [Read, Write, Edit, Glob, Grep, Bash, AskUserQuestion]
last_verified: 2026-07-16
review_by: 2027-06-22
os_version: iOS 27 / macOS 27

Error Monitoring Generator

Generates a production-ready error monitoring infrastructure with protocol-based architecture for easy provider swapping.

When This Skill Activates

• User asks to "add crash reporting" or "error monitoring"
• User mentions "Sentry", "Crashlytics", or "crash analytics"
• User wants to "track errors in production"
• User asks about "debugging production issues"

Pre-Generation Checks (CRITICAL)

1. Project Context Detection

Before generating, ALWAYS check:

# Check for existing crash reporting
rg -l "Sentry|Crashlytics|CrashReporter" --type swift

# Check Package.swift for existing SDKs
cat Package.swift | grep -i "sentry\|firebase\|crashlytics"

# Check for existing error handling patterns
rg "captureError|recordError|logError" --type swift | head -5

2. Conflict Detection

If existing crash reporting found:

• Ask: Replace, wrap existing, or create parallel system?

Configuration Questions

Ask user via AskUserQuestion:

1. **Initial provider?**

• Sentry (recommended for indie devs)
• Firebase Crashlytics (if already using Firebase)
• None (set up infrastructure only)

2. **Include breadcrumbs?**

• Yes (track navigation, user actions)
• No (errors only)

3. **Include user context?**

• Yes (anonymized user ID, app state)
• No (minimal data collection)

Generation Process

Step 1: Create Core Files

**Always generate:**

Sources/ErrorMonitoring/
├── ErrorMonitoringService.swift     # Protocol
├── ErrorContext.swift               # Breadcrumbs, user info
└── NoOpErrorMonitoring.swift        # Testing/privacy

**Based on provider selection:**

Sources/ErrorMonitoring/Providers/
├── SentryErrorMonitoring.swift      # If Sentry selected
└── CrashlyticsErrorMonitoring.swift # If Crashlytics selected

Step 2: Read Templates

Read templates from this skill:

• `templates/ErrorMonitoringService.swift`
• `templates/ErrorContext.swift`
• `templates/NoOpErrorMonitoring.swift`
• `templates/SentryErrorMonitoring.swift` (if selected)
• `templates/CrashlyticsErrorMonitoring.swift` (if selected)

Step 3: Customize for Project

Adapt templates to match:

• Project naming conventions
• Existing error types
• Bundle identifier for Sentry DSN

Step 4: Integration

**In App.swift:**

import SwiftUI

@main
struct MyApp: App {
    init() {
        // Configure error monitoring
        ErrorMonitoring.shared.configure()
    }

    var body: some Scene {
        WindowGroup {
            ContentView()
                .environment(\.errorMonitoring, ErrorMonitoring.shared.service)
        }
    }
}

**Capturing errors:**

do {
    try await riskyOperation()
} catch {
    ErrorMonitoring.shared.service.captureError(error)
}

**Adding breadcrumbs:**

ErrorMonitoring.shared.service.addBreadcrumb(
    Breadcrumb(category: "navigation", message: "Opened settings")
)

Provider Setup

Sentry

1. **Create account** at [sentry.io](https://sentry.io) 2. **Create project** for iOS/macOS 3. **Get DSN** from Project Settings > Client Keys 4. **Add to Package.swift:**

.package(url: "https://github.com/getsentry/sentry-cocoa", from: "8.0.0")

Firebase Crashlytics

1. **Add Firebase** to your project via [console.firebase.google.com](https://console.firebase.google.com) 2. **Download** GoogleService-Info.plist 3. **Add Firebase SDK** via SPM or CocoaPods 4. **Enable Crashlytics** in Firebase console

Generated Code Patterns

Protocol (Stable Interface)

protocol ErrorMonitoringService: Sendable {
    func configure()
    func captureError(_ error: Error, context: ErrorContext?)
    func captureMessage(_ message: String, level: ErrorLevel)
    func addBreadcrumb(_ breadcrumb: Breadcrumb)
    func setUser(_ user: MonitoringUser?)
    func reset()
}

Swapping Providers

// In ErrorMonitoring.swift
final class ErrorMonitoring {
    static let shared = ErrorMonitoring()

    // Change this ONE line to swap providers:
    let service: ErrorMonitoringService = SentryErrorMonitoring()
    // let service: ErrorMonitoringService = CrashlyticsErrorMonitoring()
    // let service: ErrorMonitoringService = NoOpErrorMonitoring()
}

Breadcrumb Tracking

// Automatic navigation breadcrumbs
struct ContentView: View {
    @Environment(\.errorMonitoring) var errorMonitoring

    var body: some View {
        Button("Open Details") {
            errorMonitoring.addBreadcrumb(
                Breadcrumb(category: "ui", message: "Tapped details button")
            )
            showDetails = true
        }
    }
}

Verification Checklist

After generation, verify:

• [ ] App compiles without errors
• [ ] Provider SDK added (if applicable)
• [ ] DSN/config set correctly
• [ ] Test error appears in dashboard
• [ ] Breadcrumbs captured correctly
• [ ] User context (if enabled) shows in reports
• [ ] NoOp mode works for debug/testing

Privacy Considerations

GDPR Compliance

• Use `NoOpErrorMonitoring` for EU users who opt out
• Don't capture PII in error messages
• Anonymize user IDs

App Store Guidelines

• Disclose crash reporting in privacy policy
• Use App Tracking Transparency if combining with analytics
• Don't capture unnecessary device identifiers

Privacy Manifest (iOS 17+)

Add to PrivacyInfo.xcprivacy if using Sentry/Crashlytics:

<key>NSPrivacyCollectedDataTypes</key>
<array>
    <dict>
        <key>NSPrivacyCollectedDataType</key>
        <string>NSPrivacyCollectedDataTypeCrashData</string>
        <key>NSPrivacyCollectedDataTypeLink