Two design skills · both proven

mcp-builder vs vercel-composition-patterns

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.

mcp-builder

Guide for creating high-quality MCP (Model Context Protocol) servers that enable LLMs to interact with external services through well-designed tools. Use when building MCP servers to integrate external APIs or services, whether in Python (FastMCP) or Node/TypeScript (MCP SDK).

Category: Design
Source: anthropics/skills
License: Not stated
Proof model: claude-opus-5-5
Brief: “Build an MCP server in TypeScript that gives an agent read access to a team's Linear-style issue tracker through a REST API: tools to search issues, get one issue with comments, and list a project's open issues by priority. Present it as a single HTML page with the full source of each file, the tool schemas, how errors and pagination are handled, and how to run and connect it.”
Skill commit: dbd4588

Without the skillWith mcp-builder

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Without, runWith mcp-builder, run3 independent runs per side, none selected by hand.

Download the with-skill page

vercel-composition-patterns

React composition patterns that scale. Use when refactoring components with boolean prop proliferation, building flexible component libraries, or designing reusable APIs. Triggers on tasks involving compound components, render props, context providers, or component architecture. Includes React 19 API changes.

Category: Design
Source: vercel-labs/agent-skills
License: Not stated
Proof model: claude-opus-5-5
Brief: “Refactor this React Modal component. It currently takes fourteen props, including isConfirm, isDanger, showFooter, footerAlign, hideClose, title, subtitle, icon, primaryLabel, secondaryLabel, onPrimary, onSecondary, size and children, and a dozen screens pass different combinations of them. Present the refactor as a single HTML page with the new API, the implementation, three call sites rewritten before and after, and a short note on why the new shape scales.”
Skill commit: 063bee9

Without the skillWith vercel-composition-patterns

⇆

Without, runWith vercel-composition-patterns, 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 mcp-builder or alternatives to vercel-composition-patterns.