Design vs Docs & Writing · both proven

web-design-guidelines vs writing-plans

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.

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 · 32,632 stars
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

writing-plans

Use when you have a spec or requirements for a multi-step task, before touching code

Category: Docs & Writing
Source: obra/superpowers · 301,947 stars
License: MIT
Proof model: claude-opus-5-5
Brief: “Write the implementation plan for adding team accounts to a solo-user invoicing SaaS (Next.js, Postgres, Stripe): users must be able to create a team, invite members by email, assign owner or member roles, and share clients and invoices within the team, with billing moving from the user to the team. Present the plan as a single HTML page.”
Skill commit: bb92a77

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 web-design-guidelines or alternatives to writing-plans.