Conciseness

The body is compact tables with no prose padding, but a substantial share restates stable knowledge Claude already has — 'LCP | < 2.5s', 'INP | < 200ms', 'CLS | < 0.1' are published Core Web Vitals thresholds, and the DevTools tool-selection and 'Optimize images / Enable compression' quick-win tables are generic common knowledge. This fits 'mostly efficient but includes some unnecessary explanation'; not score 4 because several sections add no information beyond what Claude knows.

Actionability

There is exactly one executable command ('python scripts/lighthouse_audit.py https://example.com'), which is copy-paste ready, but everything else is abstract mapping tables — 'Slow initial load | Large JS, render blocking', 'Big library | Import specific modules', 'Long tasks (>50ms) | UI blocking' — with no commands, code, or concrete steps for using DevTools or a bundle analyzer. Fits 'some concrete guidance but incomplete'; not score 2 because the script invocation and usage table are concrete, not score 4 because no other executable guidance exists.

Workflow Clarity

The '4-Step Process' (BASELINE → IDENTIFY → FIX → VALIDATE) is a clear ordered sequence and names validation, but the checkpoints are implicit: no instruction on how to measure the baseline, which metric or threshold confirms improvement, or what to do when validation fails (no fix-and-retry loop). This matches 'steps listed but validation gaps; checkpoints missing or implicit'; not score 4 because the validation step carries no executable detail.

Progressive Disclosure

The body is organized into seven numbered sections with clear headers, and the only bundle file (scripts/lighthouse_audit.py, verified to exist) is correctly referenced with purpose and usage in a table — good structure with content appropriately inline at this size. Not score 5 because the trailing 'When to Use' section ('This skill is applicable to execute the workflow or actions described in the overview') is vague filler placed after the closing note, and the reference-style lookup tables could be signaled toward separate reference files as the skill grows.

Specificity

The description names the domain ('Performance profiling principles') but offers only generic noun categories ('Measurement, analysis, and optimization techniques') with no concrete actions or objects — matching the anchor 'Names the domain but actions are minimal or generic' ('Processes PDF files'). Not score 3 because there are no concrete verb-object capabilities (e.g., 'Runs Lighthouse audits, profiles runtime and memory, analyzes bundle size').

Completeness

The 'what' is vague ('principles' and 'techniques' with no stated capabilities) and there is no 'when' at all — no 'Use when...' clause or equivalent trigger guidance, which also caps this dimension at 3 per the judging guidelines. This matches 'Has a vague what and no when'; not score 3 because the what never states what the skill actually does, only abstract topic categories.

Trigger Term Quality

'Performance profiling' is a phrase a user would naturally say, but coverage stops there — missing natural variations and synonyms like 'slow page', 'page speed', 'Lighthouse', 'Core Web Vitals', 'bundle size', or 'jank'. Fits 'Some relevant keywords but missing common variations or synonyms'; not score 4 because keyword coverage is a single narrow phrase with no file extensions, tool names, or colloquial variants.

Distinctiveness Conflict Risk

'Performance profiling' is a somewhat specific niche, but with no trigger guidance and only generic category words, it could overlap with general code-optimization, debugging, or monitoring skills. Fits 'Somewhat specific but could still overlap with similar skills'; not score 4 because overlap risk with adjacent optimization skills is more than minor given the absence of distinguishing triggers.