Conciseness

The body is lean — a compact lifecycle flow, one-line API glosses, a single-line guard snippet, and terse mistake/checklist bullets with no padding of concepts Claude already knows. It is docked from 5 because the "iOS 27 Updates" section carries version-stamped details ("iOS 27.1+", "September 2026 UIKit updates") that are time-sensitive and not confined to a deprecated/old-patterns section.

Actionability

Concrete guidance throughout: exact lifecycle methods with responsibilities ("makeCoordinator()", "dismantleUIView(_:coordinator:)"), an executable guard (`if uiView.text != text { uiView.text = text }`), and the four exact containment calls (addChild, addSubview, constraints, didMove(toParent:)). Not a 5 because the body contains no complete, copy-paste-ready representable example — full recipes are delegated to the reference files.

Workflow Clarity

Sequences are clear: the ordered lifecycle chain and the numbered 1–4 child-view-controller containment steps, reinforced by a Review Checklist and an explicit warning about feedback loops. It sits below 5 because checkpoints like the equality guard are stated as warnings rather than embedded validation steps, and there is no error-recovery loop — though the skill involves no destructive or batch operations that would demand one.

Progressive Disclosure

The body is a genuine overview: a "Route by Task" section maps specific needs (MKMapView, PHPicker, PDFView, hosting migration) to the four real, one-level-deep reference files, which exist in the bundle and contain no nested references, and a References section repeats the links plus official docs. This matches the top anchor of a clear overview with well-signaled, easy-to-navigate references.

Specificity

"Bridges UIKit and SwiftUI with representables, hosting controllers/configurations, coordinators, and shared observable state" plus "wrapping UIKit or third-party views/controllers, embedding SwiftUI in UIKit, ... incremental UIKit-to-SwiftUI migration" lists several specific capabilities covering the interop domain. It falls short of a 5 because "system controller surfaces" is vague and the what-clause leans on mechanism nouns rather than concrete actions.

Completeness

The what is explicit ("Bridges UIKit and SwiftUI with representables, hosting controllers/configurations, coordinators, and shared observable state") and the when is explicit with concrete trigger phrases ("Use for wrapping UIKit or third-party views/controllers, embedding SwiftUI in UIKit, system controller surfaces, or incremental UIKit-to-SwiftUI migration"). This matches the top anchor: both questions clearly and explicitly answered; it is not a 4 because the when-clause goes beyond generic guidance with multiple specific trigger scenarios.

Trigger Term Quality

Phrases like "wrapping UIKit or third-party views/controllers", "embedding SwiftUI in UIKit", and "UIKit-to-SwiftUI migration" match what users naturally say when they need this skill. A few natural terms are missing — e.g. "UIViewRepresentable", "UIHostingController", "interop", "bridge" — which users would plausibly mention by name.

Distinctiveness Conflict Risk

The UIKit↔SwiftUI bridging niche is well-defined with distinct triggers (wrapping, embedding, migration), unlikely to fire for unrelated skills. Minor overlap risk remains with general SwiftUI or iOS-development skills, and the vague phrase "system controller surfaces" slightly blurs the boundary, keeping it below a 5.