Two testing skills · both proven

receiving-code-review 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.

receiving-code-review

Use when receiving code review feedback, before implementing suggestions, especially if feedback seems unclear or technically questionable - requires technical rigor and verification, not performative agreement or blind implementation

Category: Testing
Source: obra/superpowers
License: MIT
Proof model: claude-opus-5-5
Brief: “I received this code review on my pull request that adds caching to our product API. Decide what to do with each comment and present your responses and planned changes as a single HTML page. 1. "Cache TTL of 24h is too long, prices change during the day." 2. "Use Redis instead of the in-memory Map so all 4 instances share the cache." 3. "Rename getProd to getProduct." 4. "You should rewrite this whole module in TypeScript." 5. "The cache key ignores the currency query param, so EUR users can get USD prices." 6. "Add a test."”
Skill commit: 2ce8aa1

Without the skillWith receiving-code-review

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Without, runWith receiving-code-review, 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 receiving-code-review or alternatives to writing-guidelines.