AI agent skill for MSW 2.0 — 20 rules: handler design, REST/GraphQL, test patterns. Works with Claude Code, Cursor, Codex, Windsurf.

MSW Skill

Created by Anivar Aravind

An AI agent skill for writing, reviewing, and debugging MSW (Mock Service Worker) v2 handlers, server setup, and test patterns with modern best practices.

The Problem

AI agents often generate outdated MSW v1 patterns — rest.get() instead of http.get(), res(ctx.json(...)) instead of HttpResponse.json(), (req, res, ctx) instead of ({ request, params }) — and miss critical testing best practices like server.boundary() for concurrent tests, onUnhandledRequest: 'error', and proper lifecycle hook setup. These produce code that fails to compile or silently misbehaves at runtime.

This Solution

20 rules with incorrect/correct code examples that teach agents MSW v2's actual API, handler design, server lifecycle, response construction, testing patterns, GraphQL usage, and v1-to-v2 migration. Each rule targets a specific mistake and shows exactly how to fix it.

Install

npx skills add anivar/msw-skill -g

Or with full URL:

npx skills add https://github.com/anivar/msw-skill

Baseline

• msw ^2.0.0
• TypeScript/JavaScript

What's Inside

20 Rules Across 7 Categories

Each rule file contains:

• Why it matters
• Incorrect code with explanation
• Correct code with explanation
• Decision tables and additional context

6 Deep-Dive References