Frontend vs Design · both proven

vercel-react-best-practices vs web-design-guidelines

Both skills were run through Claude twice: once on a fixed brief without the skill, once with it. The briefs differ because each is written for the job the skill claims to do, so compare each skill against its own baseline, then decide which difference matters for your work. They are in different categories, so this is a choice of job, not a head-to-head on the same job.

vercel-react-best-practices

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.

Category: Frontend
Source: vercel-labs/agent-skills
License: Not stated
Proof model: claude-opus-5-5
Brief: “Here is a slow Next.js product list page. It fetches products, reviews and inventory one after another in a client component with useEffect, renders 500 product cards at once, imports the full lodash library, and re-sorts the list on every render. Rewrite it following current React and Next.js performance practice, and present the result as a single HTML page that shows the new code, explains each change, and estimates the impact of each.”
Skill commit: 063bee9

Without the skillWith vercel-react-best-practices

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Without, runWith vercel-react-best-practices, run3 independent runs per side, none selected by hand.

Download the with-skill page

web-design-guidelines

Review UI code for Web Interface Guidelines compliance. Use when asked to "review my UI", "check accessibility", "audit design", "review UX", or "check my site against best practices".

Category: Design
Source: vercel-labs/agent-skills
License: Not stated
Proof model: claude-opus-5-5
Brief: “Build the sign-up page for Lantern, a weekly newsletter on independent software businesses. Include a hero that sells the newsletter, a preview of a recent issue, a sign-up form with name, email and a topics checklist, clear inline error and success states, three reader quotes, and a footer. Draw any imagery with inline SVG and CSS.”
Skill commit: 063bee9

Without the skillWith web-design-guidelines

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Without, runWith web-design-guidelines, run3 independent runs per side, none selected by hand.

Download the with-skill page

We don’t pick a winner for you: the pages are the evidence. Both proofs can be repeated with the brief, model and commit shown above. See alternatives to vercel-react-best-practices or alternatives to web-design-guidelines.