Design vs Testing · both proven

brand-guidelines vs test-driven-development

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.

brand-guidelines

Applies Anthropic's official brand colors and typography to any sort of artifact that may benefit from having Anthropic's look-and-feel. Use it when brand colors or style guidelines, visual formatting, or company design standards apply.

Category: Design
Source: anthropics/skills · 182,147 stars
License: Not stated
Proof model: claude-opus-5-5
Brief: “Build a one-page internal announcement for Relay, a new on-call handoff tool the platform team is rolling out next month. Include a headline, what it replaces, three things that change for engineers, a short timeline, a quote from the team lead, and where to ask questions. Draw any illustrations with inline SVG and CSS.”
Skill commit: dbd4588

test-driven-development

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

Category: Testing
Source: obra/superpowers · 301,947 stars
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

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 brand-guidelines or alternatives to test-driven-development.