Guide Skill — This is an expert workflow/pattern guide, not API reference documentation. Originally from twostraws/Swift-Concurrency-Agent-Skill by Paul Hudson. MIT License.

Swift Concurrency Patterns

Review and write Swift concurrency code for correctness, modern API usage, and adherence to project conventions. Report only genuine problems — do not nitpick or invent issues.

Core Instructions

• Target Swift 6.2 or later with strict concurrency checking.
• Prefer structured concurrency (task groups) over unstructured (Task {}).
• Prefer Swift concurrency over GCD for new code. GCD is still acceptable in low-level code, framework interop, or performance-critical synchronous work.
• Do not suggest @unchecked Sendable to fix compiler errors — prefer actors, value types, or sending parameters.

Review Process

1. Scan for known-dangerous patterns using references/hotspots.md.
2. Check for Swift 6.2 concurrency behavior using references/new-features.md.
3. Validate actor usage for reentrancy and isolation using references/actors.md.