Use when ANY iOS build fails, test crashes, Xcode misbehaves, or environment issue occurs before debugging code. Covers build failures, compilation errors, dependency conflicts, simulator problems, environment-first diagnostics.
iOS Build & Environment Router
You MUST use this skill for ANY build, environment, or Xcode-related issue before debugging application code.
When to Use
Use this router when you encounter:
- Build failures (
BUILD FAILED, compilation errors, linker errors) - Test crashes or hangs
- Simulator issues (won't boot, device errors)
- Xcode misbehavior (stale builds, zombie processes)
- Dependency conflicts (CocoaPods, SPM)
- Build performance issues (slow compilation)
- Environment issues before debugging code
Routing Logic
This router invokes specialized skills based on the specific issue:
1. Environment-First Issues → xcode-debugging
Triggers:
BUILD FAILEDwithout obvious code cause- Tests crash in clean project
- Simulator hangs or won't boot
- "No such module" after SPM changes
- Zombie
xcodebuildprocesses - Stale builds (old code still running)
- Clean build differs from incremental build
Why xcode-debugging first: 90% of mysterious issues are environment, not code. Check this BEFORE debugging code.
Invoke: /skill axiom-xcode-debugging
2. Slow Builds → build-performance
Triggers:
- Compilation takes too long
- Type checking bottlenecks
- Want to optimize build time
- Build Timeline shows slow phases
Invoke: /skill axiom-build-performance
3. SPM Dependency Conflicts → spm-conflict-resolver (Agent)
Triggers:
- SPM resolution failures
- "No such module" after adding package
- Duplicate symbol linker errors
- Version conflicts between packages
- Swift 6 package compatibility issues
- Package.swift / Package.resolved conflicts
Why spm-conflict-resolver: Specialized agent that analyzes Package.swift and Package.resolved to diagnose and resolve Swift Package Manager conflicts.
Invoke: Launch spm-conflict-resolver agent
4. Security & Privacy Audit → security-privacy-scanner (Agent)
Triggers:
- App Store submission prep
- Privacy Manifest requirements (iOS 17+)
- Hardcoded credentials in code
- Sensitive data storage concerns
- ATS violations
- Required Reason API declarations
Why security-privacy-scanner: Specialized agent that scans for security vulnerabilities and privacy compliance issues.
Invoke: Launch security-privacy-scanner agent or /axiom:audit security
5. iOS 17→18 Modernization → modernization-helper (Agent)
Triggers:
- Migrate ObservableObject to @Observable
- Update @StateObject to @State
- Adopt modern SwiftUI patterns
- Deprecated API cleanup
- iOS 17+ migration
Why modernization-helper: Specialized agent that scans for legacy patterns and provides migration paths with code examples.
Invoke: Launch modernization-helper agent or /axiom:audit modernization
6. General Dependency Issues → build-debugging
Triggers:
- CocoaPods resolution failures
- "Multiple commands produce" errors
- Framework version mismatches
- Non-SPM dependency graph conflicts
Invoke: /skill axiom-build-debugging
7. TestFlight Crash Triage → testflight-triage
Triggers:
- Beta tester reported a crash
- Crash reports in Xcode Organizer
- Crash logs aren't symbolicated
- TestFlight feedback with screenshots
- App was killed but no crash report
Why testflight-triage: Systematic workflow for investigating TestFlight crashes and reviewing beta feedback. Covers symbolication, crash interpretation, common patterns, and Claude-assisted analysis.
Invoke: /skill axiom-testflight-triage
8. App Store Connect Navigation → app-store-connect-ref
Triggers:
- How to find crashes in App Store Connect
- ASC metrics dashboard navigation
- Understanding crash-free users percentage
- Comparing crash rates between versions
- Exporting crash data from ASC
- App Store Connect API for crash data
Why app-store-connect-ref: Reference for navigating ASC crash analysis, metrics dashboards, and data export workflows.
Invoke: /skill axiom-app-store-connect-ref
9. Crash Log Analysis → crash-analyzer (Agent)
Triggers:
- User has .ips or .crash file to analyze
- User pasted crash report text
- Need to parse crash log programmatically
- Identify crash pattern from exception type
- Check symbolication status
Why crash-analyzer: Autonomous agent that parses crash reports, identifies patterns (null pointer, Swift runtime, watchdog, jetsam), and generates actionable analysis.
Invoke: Launch crash-analyzer agent or /axiom:analyze-crash
10. MetricKit API Reference → metrickit-ref
Triggers:
- MetricKit setup and subscription
- MXMetricPayload parsing (CPU, memory, launches, hitches)
- MXDiagnosticPayload parsing (crashes, hangs, disk writes)
- MXCallStackTree decoding and symbolication
- Field crash/hang collection
- Background exit metrics
Why metrickit-ref: Complete MetricKit API reference with setup patterns, payload parsing, and integration with crash reporting systems.
Invoke: /skill axiom-metrickit-ref
11. Hang Diagnostics → hang-diagnostics
Triggers:
- App hangs or freezes
- Main thread blocked for >1 second
- UI unresponsive to touches
- Xcode Organizer shows hang diagnostics
- MXHangDiagnostic from MetricKit
- Watchdog terminations (app killed during launch/background transition)
Why hang-diagnostics: Systematic diagnosis of hangs with decision tree for busy vs blocked main thread, tool selection (Time Profiler, System Trace), and 8 common hang patterns with fixes.
Invoke: /skill axiom-hang-diagnostics
Decision Tree
- Mysterious/intermittent/clean build fails? → xcode-debugging (environment-first)
- SPM dependency conflict? → spm-conflict-resolver (Agent)
- CocoaPods/other dependency conflict? → build-debugging
- Slow build time? → build-performance
- Security/privacy/App Store prep? → security-privacy-scanner (Agent)
- Modernization/deprecated APIs? → modernization-helper (Agent)
- TestFlight crash/feedback? → testflight-triage
- Navigating App Store Connect? → app-store-connect-ref
- Have a crash log (.ips/.crash)? → crash-analyzer (Agent)
- MetricKit setup/parsing? → metrickit-ref
- App hang/freeze/watchdog? → hang-diagnostics
Anti-Rationalization
| Thought | Reality |
|---|---|
| "I know how to fix this linker error" | Linker errors have 4+ root causes. xcode-debugging diagnoses all in 2 min. |
| "Let me just clean the build folder" | Clean builds mask the real issue. xcode-debugging finds the root cause. |
| "It's just an SPM issue, I'll fix Package.swift" | SPM conflicts cascade. spm-conflict-resolver analyzes the full dependency graph. |
| "The simulator is just slow today" | Simulator issues indicate environment corruption. xcode-debugging checks systematically. |
| "I'll skip environment checks, it compiles locally" | Environment-first saves 30+ min. Every time. |
When NOT to Use (Conflict Resolution)
Do NOT use ios-build for these — use the correct router instead:
| Error Type | Correct Router | Why NOT ios-build |
|---|---|---|
| Swift 6 concurrency errors | ios-concurrency | Code error, not environment |
| SwiftData migration errors | ios-data | Schema issue, not build environment |
| "Sending 'self' risks data race" | ios-concurrency | Language error, not Xcode issue |
| Type mismatch / compilation errors | Fix the code | These are code bugs |
ios-build is for environment mysteries, not code errors:
- ✅ "No such module" when code is correct
- ✅ Simulator won't boot
- ✅ Clean build fails, incremental works
- ✅ Zombie xcodebuild processes
- ❌ Swift concurrency warnings/errors
- ❌ Database migration failures
- ❌ Type checking errors in valid code
Example Invocations
User: "My build failed with a linker error"
→ Invoke: /skill axiom-xcode-debugging (environment-first diagnostic)
User: "Builds are taking 10 minutes"
→ Invoke: /skill axiom-build-performance
User: "SPM won't resolve dependencies"
→ Invoke: spm-conflict-resolver agent
User: "Two packages require different versions of the same dependency"
→ Invoke: spm-conflict-resolver agent
User: "Duplicate symbol linker error"
→ Invoke: spm-conflict-resolver agent
User: "I need to prepare for App Store security review"
→ Invoke: security-privacy-scanner agent
User: "Do I need a Privacy Manifest?"
→ Invoke: security-privacy-scanner agent
User: "Are there hardcoded credentials in my code?"
→ Invoke: security-privacy-scanner agent
User: "How do I migrate from ObservableObject to @Observable?"
→ Invoke: modernization-helper agent
User: "Update my code to use modern SwiftUI patterns"
→ Invoke: modernization-helper agent
User: "Should I still use @StateObject?"
→ Invoke: modernization-helper agent
User: "A beta tester said my app crashed"
→ Invoke: /skill axiom-testflight-triage
User: "I see crashes in App Store Connect but don't know how to investigate"
→ Invoke: /skill axiom-testflight-triage
User: "My crash logs aren't symbolicated"
→ Invoke: /skill axiom-testflight-triage
User: "I need to review TestFlight feedback"
→ Invoke: /skill axiom-testflight-triage
User: "How do I find crashes in App Store Connect?"
→ Invoke: /skill axiom-app-store-connect-ref
User: "Where's the crash-free users metric in ASC?"
→ Invoke: /skill axiom-app-store-connect-ref
User: "How do I export crash data from App Store Connect?"
→ Invoke: /skill axiom-app-store-connect-ref
User: "Analyze this crash log" [pastes .ips content]
→ Invoke: crash-analyzer agent or /axiom:analyze-crash
User: "Parse this .ips file: ~/Library/Logs/DiagnosticReports/MyApp.ips"
→ Invoke: crash-analyzer agent or /axiom:analyze-crash
User: "Why did my app crash? Here's the report..."
→ Invoke: crash-analyzer agent or /axiom:analyze-crash
User: "How do I set up MetricKit to collect crash data?"
→ Invoke: /skill axiom-metrickit-ref
User: "How do I parse MXDiagnosticPayload?"
→ Invoke: /skill axiom-metrickit-ref
User: "What's in MXCallStackTree and how do I decode it?"
→ Invoke: /skill axiom-metrickit-ref
User: "My app hangs sometimes"
→ Invoke: /skill axiom-hang-diagnostics
User: "The main thread is blocked and UI is unresponsive"
→ Invoke: /skill axiom-hang-diagnostics
User: "Xcode Organizer shows hang diagnostics for my app"
→ Invoke: /skill axiom-hang-diagnostics
User: "My app was killed by watchdog during launch"
→ Invoke: /skill axiom-hang-diagnostics
You Might Also Like
Related Skills

verify
Use when you want to validate changes before committing, or when you need to check all React contribution requirements.
facebook
test
Use when you need to run tests for React core. Supports source, www, stable, and experimental channels.
facebook
feature-flags
Use when feature flag tests fail, flags need updating, understanding @gate pragmas, debugging channel-specific test failures, or adding new flags to React.
facebook
extract-errors
Use when adding new error messages to React, or seeing "unknown error code" warnings.
facebook