Conciseness

Every sentence carries operational content the model could not infer — trap-based cleanup, stale-helper recovery, the '--kill' scoping warning, hot-swap behavior — with zero padding or explanation of known concepts. Not 4: there is nothing to trim; each line either instructs, constrains, or defines a verification bar.

Actionability

Both workflows give copy-paste-ready commands: a complete bash block with a cleanup function and trap for serve-sim, and a concrete node invocation with all flags documented (--package-target, --device, --preview-filter with a matching example like 'StatusRowView_Previews'). Not 4: no gaps remain — even the failure path ('npx serve-sim --kill "$SIM"') is executable.

Workflow Clarity

The browser workflow is a numbered sequence with an explicit validation checkpoint ('Verify that a real frame is rendering before reporting success. A loaded page alone is not proof') and error-recovery guidance for a dead terminal. Not 4: validation is explicit rather than implicit, including a Proof section defining what counts as success for both QA types.

Progressive Disclosure

The ~50-line body is a lean overview that correctly delegates implementation to the bundle: the launcher script, its lib module, and all template files referenced by it exist at the paths cited ('scripts/swiftui-preview-browser.mjs', 'lib/xcode-project.mjs', 'FocusedPreviewApp.swift', 'FocusedPreviewHotReloadRuntime.swift'). Per the rubric's simple-skill guideline, a short, well-sectioned body with no separate reference files scores 5. Not 4: sections are clearly organized (Browser Workflow, SwiftUI Preview Workflow, Support Boundary, Proof) and every cross-file pointer is one level deep and verified real.

Specificity

The description lists multiple concrete actions — 'Mirror an iOS Simulator into the Codex in-app browser', 'render SwiftUI previews from importable Swift packages', 'with hot reload' — covering both of the skill's workflows comprehensively. Not 4: there are no minor gaps; the two core capabilities are each named with concrete verbs and scope.

Completeness

It explicitly answers 'what' (mirror a simulator into the in-app browser, render SwiftUI previews with hot reload) and 'when' with a concrete 'Use when a user wants to...' clause enumerating four trigger scenarios. Not 4: the 'when' is already explicit and specific, not merely present.

Trigger Term Quality

Natural trigger phrases include 'watch or interact with an iOS app in the browser', 'see a SwiftUI preview outside Xcode Canvas', and 'iterate live on a preview' — the way users would actually phrase these requests. Not 5: a few natural synonyms are missing (e.g., 'live preview', 'Xcode previews', 'simulator streaming'); not 3: coverage is clearly good, not partial.

Distinctiveness Conflict Risk

It occupies a clear niche — iOS Simulator browser mirroring and SwiftUI preview rendering in the Codex in-app browser — with distinct triggers ('outside Xcode Canvas', 'in-app browser') that are unlikely to fire for other skills. Not 4: no meaningful overlap risk with closely related skills was identified.