Conciseness

The benchmark core (Phases 1–9, rules) is dense and efficient — raw $B commands, metric formulas, explicit thresholds — but roughly half of the ~480-line body is gstack framework boilerplate (preamble script, proactive/telemetry/lake-intro prompting flows, contributor mode, plan status footer) unrelated to benchmarking, plus a flavor persona paragraph. This fits 'mostly efficient but includes some unnecessary content that could be tightened or moved out'.

Actionability

Largely copy-paste ready: '$B goto <page-url>', '$B perf', complete $B eval one-liners for navigation/resource/bundle metrics, a git diff command for --diff, a concrete baseline JSON schema, and explicit regression thresholds. Minor gaps keep it below 5: Phase 2 delegates page discovery to 'Same as /canary' and Phase 8's --trend mode says 'Load historical baseline files' without specifying how multiple historical baselines are stored (Phase 4 writes only a single baseline.json).

Workflow Clarity

Clear 9-phase sequence (Setup → Discovery → Collection → Baseline → Comparison → Slowest Resources → Budget → Trend → Save) with argument-to-mode mapping, explicit WARNING/REGRESSION thresholds, a pre-flight browse-binary check, and a stated no-baseline fallback. It falls short of 5 because there are no error-recovery feedback loops (e.g., what to do when a page fails to load or perf data comes back empty); the read-only nature of the skill means the destructive/batch validation cap does not apply.

Progressive Disclosure

Good in-file structure (numbered phases, headers, report templates), but the ~270 lines of shared gstack framework content (preamble, telemetry flows, contributor mode, plan footer) are inlined in every skill and clearly belong in a shared one-level-deep reference; no references/ bundle exists at all. This matches 'some structure but content that should be separate is inline' rather than level 2, since sectioning and navigation within the file are solid.

Specificity

Lists multiple concrete actions with named metrics: 'Establishes baselines for page load times, Core Web Vitals, and resource sizes. Compares before/after on every PR. Tracks performance trends over time.' This covers the full workflow (measure, baseline, compare, trend) with no notable gaps, matching the comprehensive-coverage anchor rather than the 'minor gaps' level 4.

Completeness

Explicitly answers both questions: the 'what' ('Performance regression detection using the browse daemon... Compares before/after on every PR') and the 'when' ('Use when: "performance", "benchmark", "page speed"...') with concrete trigger phrases, exactly matching the level-5 anchor.

Trigger Term Quality

The 'Use when' clause provides seven natural trigger terms including synonyms and tool names: "performance", "benchmark", "page speed", "lighthouse", "web vitals", "bundle size", "load time" — covering both casual ('page speed', 'load time') and technical ('lighthouse', 'web vitals', 'bundle size') phrasings, which meets the comprehensive-coverage anchor.

Distinctiveness Conflict Risk

Clear niche (web page performance regression detection) with distinct triggers like 'lighthouse', 'web vitals', and 'bundle size'; the what-clause explicitly scopes the skill to page load times and Core Web Vitals, keeping conflict risk minimal. 'performance'/'benchmark' alone are broad, but the surrounding scoping keeps this above the level-4 minor-overlap anchor.