AvdLee/Swift-Concurrency-Agent-Skill

• **Archetype**: domain-skill-pack
• **Stars**: 1,388
• **Last pushed**: 2026-03-29
• **License**: MIT
• **Discovered**: 2026-04-12
• **Skills found**: 1

Summary

Expert-level Swift Concurrency guidance packaged as an agent skill. Covers safe concurrency patterns, performance optimization, and Swift 6 migration. Authored by a well-known iOS developer (Antoine van der Lee / SwiftLee). The single SKILL.md is exceptionally deep -- a diagnostic-first workflow with quick-fix mode, common diagnostics table, and project-settings-aware guardrails.

Assessment

HIGH VALUE for domain specialization. The skill demonstrates a gold-standard pattern for encoding language-specific expertise: it begins by reading project settings (Package.swift / .pbxproj) to determine the exact Swift language mode and strict concurrency level before offering any guidance. The diagnostic table mapping compiler errors to smallest-safe-fix + escalation references is directly extractable as a methodology pattern. The "Quick Fix Mode" vs. full analysis branching based on issue scope is a reusable decision framework. Transferable to specializations/engineering/swift-concurrency or more broadly as a template for language-migration specializations.

Extraction Priority

• High
• Rationale: Authoritative source (prominent iOS developer), deeply procedural with diagnostic-first workflow, project-settings-aware guardrails, and a reusable pattern for encoding language migration expertise. The diagnostic table + quick-fix-mode branching is a novel pattern not yet in babysitter's process library.

Processes

• **Swift Concurrency Diagnostic Workflow**: Read project settings -> capture diagnostic -> determine isolation boundary -> confirm UI-boundness -> apply smallest safe fix. Maps to a babysitter process with breakpoints for developer confirmation at each decision point.
• **Swift 6 Migration Process**: Incremental migration with guardrails against blanket @MainActor, preference for structured concurrency, and documented safety invariants for escape hatches. Could be a multi-step babysitter process with tasks for each migration phase.
• **Quick Fix Mode Decision Gate**: A reusable branching pattern -- if issue is localized + isolation is clear + fix is 1-2 steps, use quick path; otherwise escalate to full analysis. Extractable as a shared methodology pattern.

Patterns

• **Diagnostic-first workflow**: Always analyze project settings and capture exact diagnostic before proposing fixes. Prevents incorrect guidance from assumed context.
• **Smallest-safe-change principle**: Optimize for minimal behavioral change during migration. Avoid refactoring unrelated architecture.
• **Quick Fix Mode branching**: Scope-based decision gate that routes simple issues to fast path and complex issues to full analysis. Reduces overhead for trivial fixes.
• **Escape hatch documentation**: When recommending unsafe patterns (@preconcurrency, @unchecked Sendable), require documented safety invariants and removal plans.
• **Reference file architecture**: Deep reference docs (actors.md, sendable.md, threading.md, testing.md, linting.md) linked from diagnostic table for escalation.

Library Mapping

Plugin Marketplace Mapping