core-web-vitals

Optimize Core Web Vitals (LCP, INP, CLS) for better page experience and search ranking. Use when asked to "improve Core Web Vitals", "fix LCP", "reduce CLS", "optimize INP", "page experience optimization", or "fix layout shifts".

Quality

77%

Does it follow best practices?

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tessl review fix ./skills/core-web-vitals/SKILL.md

Quality

Content

65%Weight 40%Scale 1-3

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

Highly actionable content with strong code examples across all three metrics, but it is long with some restatement and does not leverage its existing reference file. Workflow sequencing and progressive disclosure are the main gaps.

Suggestions

Link references/LCP.md from the LCP section and move the detailed LCP optimizations there, keeping SKILL.md as a concise overview that points to it — this improves both progressive disclosure and conciseness.

Add an explicit optimize→measure→validate workflow (e.g., fix → re-run web-vitals/Lighthouse → confirm the metric hits 'Good' → else iterate) so verification checkpoints are sequenced rather than scattered across debugging sections.

Trim the per-metric checklists or fold them into the inline fixes to remove restatement and reduce the ~480-line footprint.

Dimension	Reasoning	Score
Conciseness	The body is mostly efficient with tight ❌/✅ code pairs, but at ~480 lines it includes brief metric definitions and per-metric checklists that restate the inline fixes, so it could be tightened rather than earning the 'every token earns its place' top anchor.	2 / 3
Actionability	It provides abundant executable HTML/JS/CSS examples, PerformanceObserver measurement snippets, and web-vitals library usage that are specific and copy-paste ready.	3 / 3
Workflow Clarity	Each metric follows an issues→fixes→checklist→debug structure, but there is no explicit measure→fix→re-measure feedback loop sequencing the work, so checkpoints are implicit rather than an ordered validated workflow.	2 / 3
Progressive Disclosure	A bundle file references/LCP.md exists but is never linked from the body, while detailed LCP optimization content is inlined in SKILL.md rather than split out and signaled — matching the 'content that should be separate is inline' and 'references not clearly signaled' anchor.	2 / 3
	Total	9 / 12 Passed

Description

90%Weight 40%Scale 1-3

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

A strong description with explicit trigger guidance and good natural-term coverage. The only weakness is that it states a single action ("Optimize") rather than enumerating several concrete capabilities.

Dimension	Reasoning	Score
Specificity	Names the domain and all three metrics ("Optimize Core Web Vitals (LCP, INP, CLS)") but uses a single verb rather than listing multiple distinct concrete actions, matching the 'names domain and some actions' anchor rather than the 'lists multiple specific concrete actions' anchor.	2 / 3
Completeness	It explicitly answers what ("Optimize Core Web Vitals ... for better page experience and search ranking") and when (an explicit "Use when asked to ..." clause), satisfying both halves with explicit triggers.	3 / 3
Trigger Term Quality	The "Use when asked to 'improve Core Web Vitals', 'fix LCP', 'reduce CLS', 'optimize INP', 'page experience optimization', or 'fix layout shifts'" clause gives good coverage of natural terms a user would actually say.	3 / 3
Distinctiveness Conflict Risk	The Core Web Vitals / LCP / INP / CLS niche is narrow and the triggers are distinctive, making conflict with other skills unlikely.	3 / 3
	Total	11 / 12 Passed

Validation

93%

Warnings & errors only

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation — 15 / 16 Passed

Validation for skill structure

Criteria	Description	Result
relative_links	Relative link issues: 1 suspicious	Warning

	Total	15 / 16 Passed

Repository: addyosmani/web-quality-skills
Path: skills/core-web-vitals/SKILL.md
Commit: 95d6e25

Reviewed: 9 days ago

Table of Contents

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