perf-web-optimization

Optimize web performance: bundle size, images, caching, lazy loading, and overall page speed. Use when site is slow, reducing bundle size, fixing layout shifts, improving Time to Interactive, or optimizing for Lighthouse scores. Triggers on: web performance, bundle size, page speed, slow site, lazy loading. Do NOT use for Core Web Vitals-specific fixes (use core-web-vitals), running Lighthouse audits (use perf-lighthouse), or Astro-specific optimization (use perf-astro).

Quality

90%

Does it follow best practices?

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Adds up to 20 points to the overall score

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Securityby

Passed

No findings from the security scan

Quality

Content

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

A highly actionable, token-efficient reference with excellent progressive disclosure to real bundle files. The main weakness is workflow clarity: the five-phase process is only named at a high level with no concrete per-phase validation steps inline.

Suggestions

Expand the 'Measure -> Identify -> Prioritize -> Implement -> Verify' line into a short sequenced workflow with a concrete command per phase (e.g., a Lighthouse/audit command for Measure and Verify) and an explicit validation checkpoint before declaring optimization complete.

Tie the existing Checklist section explicitly to the Verify phase so the verification step is part of the workflow rather than a standalone section.

Add a brief prioritization heuristic to the Prioritize phase (e.g., 'largest LCP element first, then INP offenders') so the sequence drives concrete decisions instead of only naming phases.

Dimension	Reasoning	Score
Conciseness	Lean reference-style content that assumes Claude's competence — numeric metric thresholds, copy-paste code, and terse annotations like 'common INP killer' with no concept-explaining fluff, matching the 'every token earns its place' anchor.	5 / 5
Actionability	Provides fully executable, copy-paste-ready code and commands across images, fonts, third-party scripts, critical CSS, bundle analysis, code splitting, and caching headers, covering the common cases; the two intentionally user-specific placeholders are justified templates, not gaps.	5 / 5
Workflow Clarity	The 'Measure -> Identify -> Prioritize -> Implement -> Verify' sequence is named but presented as a single high-level line with no per-phase commands, and the Verify checkpoint delegates externally to perf-lighthouse, leaving validation implicit rather than tied into the workflow.	3 / 5
Progressive Disclosure	Clear overview body with well-signaled one-level-deep references to the three real bundle files (core-web-vitals.md, bundle-optimization.md, image-optimization.md), each annotated with its scope, with in-depth patterns appropriately split out.	5 / 5
	Total	18 / 20 Passed

Description

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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, well-structured description that clearly states capabilities, provides concrete natural-language triggers, and draws explicit boundaries against sibling perf skills. The only minor gap is synonym breadth in the trigger list.

Dimension	Reasoning	Score
Specificity	Lists multiple concrete optimization targets comprehensively: 'bundle size, images, caching, lazy loading, and overall page speed', matching the comprehensive-coverage anchor rather than the 4 anchor's 'minor gaps'.	5 / 5
Completeness	Explicitly answers both what ('Optimize web performance: bundle size, images, caching, lazy loading...') and when ('Use when site is slow... Triggers on: web performance, bundle size, page speed, slow site, lazy loading.') with concrete trigger phrases.	5 / 5
Trigger Term Quality	Good natural-term coverage including 'slow site', 'page speed', 'bundle size', 'lazy loading', and 'site is slow', but missing some common synonym variations users might say, placing it just below the comprehensive 5 anchor.	4 / 5
Distinctiveness Conflict Risk	Clear niche with explicit exclusion boundaries ('Do NOT use for Core Web Vitals-specific fixes (use core-web-vitals), running Lighthouse audits (use perf-lighthouse), or Astro-specific optimization (use perf-astro)') minimizing conflict with sibling skills.	5 / 5
	Total	19 / 20 Passed

Validation

100%

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 — 16 / 16 Passed

Validation for skill structure

No warnings or errors.

Repository: tech-leads-club/agent-skills
Path: packages/skills-catalog/skills/(performance)/perf-web-optimization/SKILL.md
Commit: fe318be

Reviewed: 3 days ago

Table of Contents

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