React and Next.js performance optimization guidelines from Vercel Engineering. This skill should be used when writing, reviewing, or refactoring React/Next.js code to ensure optimal performance patterns. Triggers on tasks involving React components, Next.js pages, data fetching, bundle optimization, or performance improvements.
78
Quality
77%
Does it follow best practices?
Impact
66%
1.15xAverage score across 3 eval scenarios
Passed
No known issues
Optimize this skill with Tessl
npx tessl skill review --optimize ./skills/data/03-developer-reactbestpractices/SKILL.mdQuality
Discovery
82%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 a solid description that clearly communicates when to use the skill and covers relevant trigger terms. Its main weakness is the lack of specific concrete actions - it describes the domain well but doesn't enumerate what specific optimizations or techniques the skill provides. The distinctiveness could be improved by emphasizing performance-specific triggers more strongly.
Suggestions
Add specific concrete actions like 'implement code splitting, lazy load components, optimize images, reduce bundle size, configure caching strategies'
Strengthen distinctiveness by adding performance-specific trigger terms like 'slow page load', 'large bundle', 'Core Web Vitals', 'lighthouse score' to differentiate from general React/Next.js skills
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | Names the domain (React/Next.js performance) and mentions some areas (components, pages, data fetching, bundle optimization) but doesn't list concrete actions like 'lazy load components', 'implement code splitting', or 'optimize images'. | 2 / 3 |
Completeness | Clearly answers both what ('React and Next.js performance optimization guidelines') and when ('when writing, reviewing, or refactoring React/Next.js code' plus explicit 'Triggers on' clause listing specific scenarios). | 3 / 3 |
Trigger Term Quality | Good coverage of natural terms users would say: 'React components', 'Next.js pages', 'data fetching', 'bundle optimization', 'performance improvements'. These are terms developers naturally use when discussing these topics. | 3 / 3 |
Distinctiveness Conflict Risk | While it specifies React/Next.js performance, it could overlap with general React skills or Next.js development skills. The performance focus helps but 'React components' and 'Next.js pages' are broad triggers that might conflict with non-performance React/Next.js skills. | 2 / 3 |
Total | 10 / 12 Passed |
Implementation
72%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
This skill excels at organization and progressive disclosure, providing a well-structured index of 45 performance rules with clear prioritization. However, it functions more as a table of contents than an actionable skill - the actual implementation guidance and code examples are deferred entirely to referenced files, reducing immediate actionability.
Suggestions
Include 2-3 inline code examples for the highest-impact rules (e.g., async-parallel with Promise.all, bundle-barrel-imports) to make the skill immediately actionable without requiring file lookups
Add a brief workflow section explaining how to approach performance optimization: e.g., 'Start with CRITICAL rules, measure with Lighthouse, then address HIGH priority items'
Consider adding a validation checkpoint like 'After applying changes, verify bundle size reduction with `next build` output or measure Core Web Vitals'
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The content is lean and efficient, presenting 45 rules across 8 categories in a well-organized table and list format. It assumes Claude's competence with React/Next.js and doesn't waste tokens explaining basic concepts. | 3 / 3 |
Actionability | While the rule names and categories are clear, the skill itself contains no executable code examples - it only references that examples exist in separate rule files. The quick reference provides rule IDs but not the actual implementation guidance. | 2 / 3 |
Workflow Clarity | The 'When to Apply' section provides clear triggers, and the priority table helps sequence which optimizations to tackle first. However, there's no explicit workflow for how to apply multiple rules, validate improvements, or handle conflicts between rules. | 2 / 3 |
Progressive Disclosure | Excellent structure with a clear overview, priority-ordered categories, and well-signaled one-level-deep references to individual rule files (rules/*.md) and the full compiled document (AGENTS.md). Navigation is intuitive. | 3 / 3 |
Total | 10 / 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.
6213d1a
Table of Contents
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