perf-astro
Astro-specific performance optimizations for 95+ Lighthouse scores. Covers critical CSS inlining, compression, font loading, and LCP optimization. Use when optimizing Astro site performance, improving Astro Lighthouse scores, or configuring astro-critters. Do NOT use for non-Astro sites (use perf-web-optimization or core-web-vitals) or running Lighthouse audits (use perf-lighthouse).
95
93%
Does it follow best practices?
Impact
Pending
No eval scenarios have been run
Passed
No known issues
Quality
Discovery
100%Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.
This is an excellent skill description that hits all the marks. It provides specific capabilities, natural trigger terms, explicit use/don't-use guidance, and clear disambiguation from related skills. The inclusion of negative triggers ('Do NOT use for non-Astro sites') with alternative skill references is a best practice that further strengthens distinctiveness.
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | Lists multiple specific concrete actions: critical CSS inlining, compression, font loading, and LCP optimization. Also specifies a concrete target (95+ Lighthouse scores). | 3 / 3 |
Completeness | Clearly answers both 'what' (Astro performance optimizations covering CSS inlining, compression, font loading, LCP) and 'when' (explicit 'Use when' clause with triggers, plus 'Do NOT use' guidance for disambiguation). | 3 / 3 |
Trigger Term Quality | Excellent coverage of natural terms users would say: 'Astro', 'Lighthouse scores', 'performance', 'critical CSS', 'font loading', 'LCP', 'astro-critters', 'compression'. These are terms a developer would naturally use when seeking Astro performance help. | 3 / 3 |
Distinctiveness Conflict Risk | Highly distinctive with clear niche (Astro-specific performance). The explicit 'Do NOT use' clauses with alternative skill references (perf-web-optimization, core-web-vitals, perf-lighthouse) actively prevent conflicts with related skills. | 3 / 3 |
Total | 12 / 12 Passed |
Implementation
87%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
This is a strong, well-crafted skill that provides concrete, actionable Astro performance optimization guidance with excellent code examples and efficient use of tokens. Its main weakness is the lack of explicit validation steps—there's no feedback loop for verifying that the optimizations actually achieved the 95+ Lighthouse target or troubleshooting when they don't. The checklist at the end is helpful but focuses on setup completion rather than outcome verification.
Suggestions
Add a validation/feedback loop after the Measuring section: e.g., 'If score < 95: check build output for critters inlining percentage, verify LCP image is preloaded via DevTools Network tab, confirm compress output sizes'
Include expected build output or Lighthouse score ranges so Claude can verify optimizations are working correctly
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The content is lean and efficient. Every section serves a purpose with no unnecessary explanations of basic concepts. The brief descriptions of what astro-critters does are justified since they describe library-specific behavior, not general knowledge. | 3 / 3 |
Actionability | Fully executable code examples throughout: install commands, complete astro.config.mjs configuration, a full Layout.astro template with copy-paste ready patterns for font loading, LCP preloading, and script deferral. The Lighthouse command is also directly runnable. | 3 / 3 |
Workflow Clarity | The skill provides a clear setup sequence and a checklist, but lacks explicit validation/verification steps. After configuring integrations and the layout pattern, there's no guidance on verifying the build output, checking that critters actually inlined CSS correctly, or a feedback loop for when Lighthouse scores don't meet the 95+ target. | 2 / 3 |
Progressive Disclosure | Well-structured with clear sections progressing from quick setup to integrations to layout pattern to measuring. Cross-references to related skills (perf-lighthouse, perf-web-optimization) are clearly signaled and one level deep. Content is appropriately scoped without being monolithic. | 3 / 3 |
Total | 11 / 12 Passed |
Validation
100%Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.
Validation — 11 / 11 Passed
Validation for skill structure
No warnings or errors.
- Repository
- tech-leads-club/agent-skills
- Commit
906a57d
- Reviewed
Table of Contents
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