msw-setup

SkillDev tools

Scaffold MSW and @msw-mcp/client in a web project for AI-driven dynamic mocks. Use when the user asks to set up MSW, add mocking to a new app, or migrate an existing MSW project.

Available today. Use it from your connected AI after setup.

Connect ahel once, and every AI you use reads what you have installed.

Then ask your AI: use the msw-setup skill

What this skill tells your AI

The instructions your AI receives, as published by jasonboy/msw-mcp in skills/msw-setup/SKILL.md and read by ahel’s review.

Project scaffolding for MSW + the MCP client bridge. For runtime handler changes after setup, use the msw-cli skill.

Workflow

  1. Run msw-cli setup in the project root (optional: --framework vite).
  2. Follow the printed setup guide step by step (detect bundler, install deps, create mocks/, env vars, entry point).
  3. Run msw-cli open and set the app's WebSocket URL to the URL from the output.
  4. Run msw-cli status after starting the dev server — confirm connected: true (this only proves the WebSocket bridge, not that the first browser requests were intercepted).
  5. Hard reload the app and confirm in DevTools → Network that initial API calls are mocked. This catches render-before-mock races that msw-cli status misses.
  6. Use msw-cli add (and related commands) to manage mocks at runtime.

Do not duplicate the full setup guide in chat — execute from msw-cli setup output.

Notes

  • Ask permission before npm install / npx msw init (as the guide describes).
  • The WebSocket URL env var name depends on the framework: NEXT_PUBLIC_MSW_WS_URL (Next.js), VITE_MSW_WS_URL (Vite), or MSW_WS_URL (Rspack/Rsbuild/Webpack) — must match the port from msw-cli open. (MCP_SERVER_URL is accepted as a legacy fallback.)
  • Next.js App Router: app/layout.tsx is a Server Component; the MSW bootstrap must be a 'use client' gate so the app subtree does not mount (and fetch) before initMocks() finishes. Follow the guide’s gated MswProvider pattern — do not start MSW in a parallel useEffect while rendering the full tree.
  • MCP users can still use /msw-setup in an MCP client; the same guide backs both paths.

Signals

GitHub stars
81
Forks
2
Last commit
Jun 2026
Advanced
Catalog kind
skill
Gateway key
msw-setup
Source
github.com/jasonboy/msw-mcp