axiom-ios-concurrency▌
charleswiltgen/axiom · updated Apr 8, 2026
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You MUST use this skill for ANY concurrency, async/await, threading, or Swift 6 concurrency work.
iOS Concurrency Router
You MUST use this skill for ANY concurrency, async/await, threading, or Swift 6 concurrency work.
When to Use
Use this router when:
- Writing async/await code
- Seeing concurrency errors (data races, actor isolation)
- Working with @MainActor
- Dealing with Sendable conformance
- Optimizing Swift performance
- Migrating to Swift 6 concurrency
- App freezes during loading (likely main thread blocking)
Conflict Resolution
ios-concurrency vs ios-performance: When app freezes or feels slow:
- Try ios-concurrency FIRST — Main thread blocking is the #1 cause of UI freezes. Check for synchronous work on @MainActor before profiling.
- Only use ios-performance if concurrency fixes don't help — Profile after ruling out obvious blocking.
ios-concurrency vs ios-build: When seeing Swift 6 concurrency errors:
- Use ios-concurrency, NOT ios-build — Concurrency errors are CODE issues, not environment issues
- ios-build is for "No such module", simulator issues, build failures unrelated to Swift language errors
ios-concurrency vs ios-data: When concurrency errors involve Core Data or SwiftData:
- Core Data threading (NSManagedObjectContext thread confinement, performBackgroundTask) → use ios-data first — Core Data has its own threading model distinct from Swift concurrency
- SwiftData + @MainActor ModelContext → use ios-concurrency — This is Swift concurrency isolation
- General "background saves losing data" → use ios-data first — Framework-specific threading rules take priority
Rationale: A 2-second freeze during data loading is almost always await on main thread or missing background dispatch. Domain knowledge solves this faster than Time Profiler. Core Data threading violations need Core Data-specific fixes, not generic concurrency patterns.
Routing Logic
Swift Concurrency Issues
Swift 6 concurrency patterns → /skill axiom-swift-concurrency
- async/await patterns
- @MainActor usage
- Actor isolation
- Sendable conformance
- Data race prevention
- Swift 6 migration
Swift concurrency API reference → /skill axiom-swift-concurrency-ref
- Actor definition, reentrancy, global actors
- Sendable patterns, @unchecked Sendable
- Task/TaskGroup/cancellation API
- AsyncStream, continuations
- DispatchQueue → actor migration
Swift performance → /skill axiom-swift-performance
- Value vs reference types
- Copy-on-write optimization
- ARC overhead
- Generic specialization
- Collection performance
Synchronous actor access → /skill axiom-assume-isolated
- MainActor.assumeIsolated
- @preconcurrency protocol conformances
- Legacy delegate callbacks
- Testing MainActor code synchronously
Thread-safe primitives → /skill axiom-synchronization
- Mutex (iOS 18+)
- OSAllocatedUnfairLock (iOS 16+)
- Atomic types
- Lock vs actor decision
Parameter ownership → /skill axiom-ownership-conventions
- borrowing/consuming modifiers
- Noncopyable types (~Copyable)
- ARC traffic reduction
- consume operator
Concurrency profiling → /skill axiom-concurrency-profiling
- Swift Concurrency Instruments template
- Actor contention diagnosis
- Thread pool exhaustion
- Task visualization
Combine reactive patterns → /skill axiom-combine-patterns
- Publisher/Subscriber lifecycle, AnyCancellable
- Combine vs async/await decision
- @Published + ObservableObject
- Operator patterns, bridging
Automated Scanning
Concurrency audit → Launch concurrency-auditor agent or /axiom:audit concurrency (Swift 6 strict concurrency violations, unsafe Task captures, missing @MainActor, Sendable violations, actor isolation problems)
Decision Tree
- Data races / actor isolation / @MainActor / Sendable? → swift-concurrency 1a. Need specific API syntax (actor definition, TaskGroup, AsyncStream, continuation)? → swift-concurrency-ref
- Writing async/await code? → swift-concurrency
- Swift 6 migration? → swift-concurrency
- assumeIsolated / @preconcurrency? → assume-isolated
- Mutex / lock / synchronization? → synchronization
- borrowing / consuming / ~Copyable? → ownership-conventions
- Profile async performance / actor contention? → concurrency-profiling
- Value type / ARC / generic optimization? → swift-performance
- Want automated concurrency scan? → concurrency-auditor (Agent)
- Combine / @Published / AnyCancellable / reactive streams? → combine-patterns
Anti-Rationalization
| Thought | Reality |
|---|---|
| "Just add @MainActor and it'll work" | @MainActor has isolation inheritance rules. swift-concurrency covers all patterns. |
| "I'll use nonisolated(unsafe) to silence the warning" | Silencing warnings hides data races. swift-concurrency shows the safe pattern. |
| "It's just one async call" | Even single async calls have cancellation and isolation implications. swift-concurrency covers them. |
| "I know how actors work" | Actor reentrancy and isolation rules changed in Swift 6.2. swift-concurrency is current. |
| "I'll fix the Sendable warnings later" | Sendable violations cause runtime crashes. swift-concurrency fixes them correctly now. |
| "Combine is dead, just use async/await" | Combine has no deprecation notice. Rewriting working pipelines wastes time and introduces bugs. combine-patterns covers incremental migration. |
Critical Patterns
Swift 6 Concurrency (swift-concurrency):
- Progressive journey: single-threaded → async → concurrent → actors
- @concurrent attribute for forced background execution
- Isolated conformances
- Main actor mode for approachable concurrency
- 11 copy-paste patterns
Swift Performance (swift-performance):
- ~Copyable for non-copyable types
- Copy-on-write (COW) patterns
- Value vs reference type decisions
- ARC overhead reduction
- Generic specialization
Example Invocations
User: "I'm getting 'data race' errors in Swift 6"
→ Invoke: /skill axiom-swift-concurrency
User: "How do I use @MainActor correctly?"
→ Invoke: /skill axiom-swift-concurrency
User: "My app is slow due to unnecessary copying"
→ Invoke: /skill axiom-swift-performance
User: "Should I use async/await for this network call?"
→ Invoke: /skill axiom-swift-concurrency
User: "How do I use assumeIsolated?"
→ Invoke: /skill axiom-assume-isolated
User: "My delegate callback runs on main thread, how do I access MainActor state?"
→ Invoke: /skill axiom-assume-isolated
User: "Should I use Mutex or actor?"
→ Invoke: /skill axiom-synchronization
User: "What's the difference between os_unfair_lock and OSAllocatedUnfairLock?"
→ Invoke: /skill axiom-synchronization
User: "What does borrowing do in Swift?"
→ Invoke: /skill axiom-ownership-conventions
User: "How do I use ~Copyable types?"
→ Invoke: /skill axiom-ownership-conventions
User: "My async code is slow, how do I profile it?"
→ Invoke: /skill axiom-concurrency-profiling
User: "I think I have actor contention, how do I diagnose it?"
→ Invoke: /skill axiom-concurrency-profiling
User: "My Core Data saves lose data from background tasks"
→ Route to: ios-data router (Core Data threading is framework-specific)
User: "How do I create a TaskGroup?"
→ Invoke: /skill axiom-swift-concurrency-ref
User: "What's the AsyncStream API?"
→ Invoke: /skill axiom-swift-concurrency-ref
User: "How do I create a custom global actor?"
→ Invoke: /skill axiom-swift-concurrency-ref
User: "How do I convert a completion handler to async?"
→ Invoke: /skill axiom-swift-concurrency-ref
User: "What are the actor reentrancy rules?"
→ Invoke: /skill axiom-swift-concurrency-ref
User: "My Combine pipeline silently stopped producing values"
→ Invoke: /skill axiom-combine-patterns
User: "Should I use Combine or async/await for this data flow?"
→ Invoke: /skill axiom-combine-patterns
User: "How do I bridge a Combine publisher into async/await code?"
→ Invoke: /skill axiom-combine-patterns
User: "AnyCancellable is leaking memory"
→ Invoke: /skill axiom-combine-patterns
User: "Check my code for Swift 6 concurrency issues"
→ Invoke: concurrency-auditor agent
How to use axiom-ios-concurrency on Cursor
AI-first code editor with Composer
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 axiom-ios-concurrency
Execute installation command
Execute the skills CLI command in your project's root directory to begin installation:
The skills CLI fetches axiom-ios-concurrency from GitHub repository charleswiltgen/axiom and configures it for Cursor.
Select Cursor when prompted
The CLI will show a list of available agents. Use arrow keys to navigate and space to select Cursor:
Verify installation
Confirm successful installation by checking the skill directory location:
Reload or restart Cursor to activate axiom-ios-concurrency. Access the skill through slash commands (e.g., /axiom-ios-concurrency) 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.
List & Monetize Your Skill
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Use Cases▌
User Story & Requirements Generation
Create detailed user stories, acceptance criteria, and feature specs
Example
Generate user stories for 'password reset feature' with acceptance criteria, edge cases, and test scenarios
Reduce spec writing time by 50%, ensure comprehensive coverage
Competitive Analysis
Research competitors, compare features, identify gaps
Example
Analyze 5 competitor products, create feature comparison matrix, suggest differentiation opportunities
Complete competitive research in 2 hours instead of 2 days
Roadmap Prioritization
Evaluate features using frameworks (RICE, ICE, Kano) and create prioritized backlogs
Example
Score 20 feature ideas using RICE framework, generate prioritized roadmap with rationale
Make data-driven prioritization decisions faster
Stakeholder Communication
Draft PRDs, status updates, and stakeholder presentations
Example
Create executive summary of Q3 roadmap, monthly progress report, feature launch announcement
Save 3-5 hours/week on communication overhead
Implementation Guide▌
Prerequisites
- ›Claude Desktop or compatible AI client
- ›Access to product documentation and roadmap tools (Jira, Notion, etc.)
- ›Understanding of product management frameworks (RICE, Jobs-to-be-Done, etc.)
- ›Stakeholder contact information and communication channels
Time Estimate
30-60 minutes to see productivity improvements
Installation Steps
- 1.Install product management skill
- 2.Start with user story generation for known feature
- 3.Progress to competitive analysis: research 2-3 competitors
- 4.Use for roadmap prioritization: apply RICE/ICE scoring
- 5.Draft stakeholder communications and refine based on feedback
- 6.Build template library for recurring PM tasks
- 7.Share effective prompts with product team
Common Pitfalls
- ⚠Not validating competitive research—verify facts before sharing
- ⚠Accepting user stories without involving engineering team
- ⚠Over-relying on frameworks without qualitative judgment
- ⚠Not customizing outputs to company culture and communication style
- ⚠Skipping stakeholder validation of generated requirements
Best Practices▌
✓ Do
- +Validate research and competitive analysis with real data
- +Collaborate with engineering when generating technical requirements
- +Customize frameworks and templates to your company context
- +Use skill for first drafts, refine with stakeholder input
- +Document successful prompt patterns for PM tasks
- +Combine AI efficiency with human judgment and intuition
✗ Don't
- −Don't publish competitive analysis without fact-checking
- −Don't finalize user stories without engineering review
- −Don't make prioritization decisions solely on AI scoring
- −Don't skip customer validation of generated requirements
- −Don't ignore company-specific context and culture
💡 Pro Tips
- ★Provide context: company goals, constraints, customer feedback
- ★Ask for alternatives: 'Show 3 ways to prioritize this roadmap'
- ★Request stakeholder-specific formatting: 'Executive summary vs. engineering spec'
- ★Use skill for 70% generation + 30% customization to company needs
When to Use This▌
✓ Use When
Use for user story writing, competitive research, roadmap prioritization, stakeholder communication, and PRD drafting. Best for reducing repetitive documentation and research work.
✗ Avoid When
Avoid for strategic product vision (requires deep customer empathy), pricing decisions (needs market and financial expertise), or when face-to-face customer discovery is more valuable than speed.
Learning Path▌
- 1Basic: user stories, feature specs, status updates
- 2Intermediate: competitive analysis, prioritization frameworks, PRDs
- 3Advanced: product strategy, go-to-market planning, OKR setting
- 4Expert: product vision, market positioning, business model innovation
Discussion
Product Hunt–style comments (not star reviews)- No comments yet — start the thread.
Ratings
4.7★★★★★30 reviews- ★★★★★Pratham Ware· Dec 16, 2024
axiom-ios-concurrency reduced setup friction for our internal harness; good balance of opinion and flexibility.
- ★★★★★Hiroshi Sanchez· Dec 16, 2024
Useful defaults in axiom-ios-concurrency — fewer surprises than typical one-off scripts, and it plays nicely with `npx skills` flows.
- ★★★★★Nia Kim· Dec 12, 2024
Registry listing for axiom-ios-concurrency matched our evaluation — installs cleanly and behaves as described in the markdown.
- ★★★★★Aanya Mehta· Nov 7, 2024
axiom-ios-concurrency has been reliable in day-to-day use. Documentation quality is above average for community skills.
- ★★★★★Aanya Anderson· Oct 26, 2024
Solid pick for teams standardizing on skills: axiom-ios-concurrency is focused, and the summary matches what you get after install.
- ★★★★★Aarav Singh· Sep 17, 2024
We added axiom-ios-concurrency from the explainx registry; install was straightforward and the SKILL.md answered most questions upfront.
- ★★★★★Sakshi Patil· Sep 13, 2024
I recommend axiom-ios-concurrency for anyone iterating fast on agent tooling; clear intent and a small, reviewable surface area.
- ★★★★★Diya Patel· Sep 13, 2024
Registry listing for axiom-ios-concurrency matched our evaluation — installs cleanly and behaves as described in the markdown.
- ★★★★★Meera Diallo· Sep 9, 2024
Useful defaults in axiom-ios-concurrency — fewer surprises than typical one-off scripts, and it plays nicely with `npx skills` flows.
- ★★★★★Meera Huang· Aug 28, 2024
I recommend axiom-ios-concurrency for anyone iterating fast on agent tooling; clear intent and a small, reviewable surface area.
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