Design vs Testing · both proven

canvas-design vs writing-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.

canvas-design

Create beautiful visual art in .png and .pdf documents using design philosophy. You should use this skill when the user asks to create a poster, piece of art, design, or other static piece. Create original visual designs, never copying existing artists' work to avoid copyright violations.

Category: Design
Source: anthropics/skills
License: Not stated
Proof model: claude-opus-5-5
Brief: “Build the one-page site for Blue Hour, a monthly jazz night at a small club: a poster-style hero with a drawn inline SVG illustration, the lineup with short bios, the schedule, a photo-strip section drawn with SVG, ticket tiers, and a footer with the address. Make it feel like a printed poster brought to the web, with motion.”
Skill commit: dbd4588

Without the skillWith canvas-design

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

Download the with-skill page

writing-guidelines

Review docs/prose for Writing Guidelines compliance. Use when asked to "review my docs", "check writing style", "audit prose", "review docs voice and tone", or "check this page against the writing handbook".

Category: Testing
Source: vercel-labs/agent-skills
License: Not stated
Proof model: claude-opus-5-5
Brief: “Review and rewrite this getting-started page for Pipewell, a data pipeline CLI. The draft opens with two paragraphs of company history, mixes 'you' and 'the user', buries the install command in the fourth paragraph, uses passive voice throughout, and ends without a next step. Write the improved page as a single HTML document, followed by a short list of what you changed and why.”
Skill commit: 063bee9

Without the skillWith writing-guidelines

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Without, runWith writing-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 canvas-design or alternatives to writing-guidelines.