Testing vs Design · both proven

test-driven-development vs ui-styling

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.

test-driven-development

Use when implementing any feature or bugfix, before writing implementation code

Category: Testing
Source: obra/superpowers
License: MIT
Proof model: claude-opus-5-5
Brief: “Implement a function that parses a cron expression (the standard five fields) and returns the next run time after a given date, in TypeScript. Present the work as a single HTML page with two columns: the test file on the left and the implementation on the right, each in a code block, with a short note at the top on the order you did things in and anything you decided not to support.”
Skill commit: bb92a77

Without the skillWith test-driven-development

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Without, runWith test-driven-development, run3 independent runs per side, none selected by hand.

Download the with-skill page

ui-styling

Create beautiful, accessible user interfaces with shadcn/ui components (built on Radix UI + Tailwind), Tailwind CSS utility-first styling, and canvas-based visual designs. Use when building user interfaces, implementing design systems, creating responsive layouts, adding accessible components (dialogs, dropdowns, forms, tables), customizing themes and colors, implementing dark mode, generating…

Category: Design
Source: nextlevelbuilder/ui-ux-pro-max-skill
License: MIT
Proof model: claude-opus-5-5
Brief: “Build the main screen of Quayside, an internal tool a small logistics company uses to track container shipments: a sidebar, a filter bar, a table of 12 shipments with status, ETA and port, a detail panel for the selected shipment with a timeline, and an empty state for when filters match nothing. Make it accessible and keyboard friendly.”
Skill commit: d14efff

Without the skillWith ui-styling

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Without, runWith ui-styling, 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 test-driven-development or alternatives to ui-styling.