Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add fubits1/svelte-skills --skill mswgit clone --depth 1 https://github.com/fubits1/svelte-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/fubits1/svelte-skills/msw)<a href="https://agentmods.dev/skills/fubits1/svelte-skills/msw"><img src="https://agentmods.dev/badge/skills/fubits1/svelte-skills/msw/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/fubits1/svelte-skills/msw"><img src="https://agentmods.dev/badge/skills/fubits1/svelte-skills/msw.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00062 | $0.04331 |
| Opus 5.5 | $0.00025 | $0.01732 |
| Sonnet 5.5 | $0.00012 | $0.00866 |
| Haiku 4.5 | $0.00006 | $0.00433 |
Grade A, and why
msw scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 12d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 112 lines — stays where its author put it; the contents beside it link to each section on GitHub.
MSW (Mock Service Worker)
MSW's API is documented at mswjs.io/docs, with a debugging runbook and integration guides for Vitest without Vite and Vite; mswjs.io serves no llms.txt. The Vitest page sends Vite projects to the Vite page, which has no Vitest setup; follow the Vitest browser steps below. This skill covers where the Svelte, Storybook and Vitest toolchain departs from those pages.
vi.mock replaces a module and MSW replaces the network. Use MSW to apply svelte-5:testing-svelte's "Mock at the right seam" to HTTP, so the component, fetch, Request and Response stay real. Not for replacing a module (vi.mock, svelte-5:testing-svelte) or for a one-off override in a Playwright test (page.route, see E2E below).
Three surfaces, three handler sets
| Surface | Started in | Handler set |
|---|---|---|
| Storybook | mswLoader() in .storybook/preview.ts |
full: every story must be hermetic |
| Vitest browser | setupWorker in a setup file, once per page |
narrow: per-test worker.use(), plus a guard that fails on unmocked requests |
| Dev app | gated entry import (Vite integration); on SvelteKit, init in hooks.client/hooks.server via virtual:msw |
narrow: only what the backend lacks |
Keep one handler set per surface; one shared array makes dev stop reaching your backend once a story adds a catch-all (handlers). On SvelteKit, start from the @msw/sveltekit add-on rather than hand-wiring hooks; read the code sv will run before running it (a community add-on): sveltekit.
Vitest browser setup
Before step 1: install msw (pnpm add -D msw, or the @msw/sveltekit add-on on SvelteKit), serve the worker script (next section), and create the mocks index module the setup files import (handlers, "One handler set per surface").
What ships with it
5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 12d ago Changed · +24 lines · -2 tokens per session b8f2c6233c20
- 1mo ago Changed · +2 lines 5277e80cbec2
- 2mo ago First seen · 86 lines · 64 tokens per session scan A 0055d5c74e03
msw is a skill published in the GitHub repository fubits1/svelte-skills (10 stars, last pushed 12d ago), licensed MIT. It adds 62 tokens to every session and 4,331 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
msw compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| mswfubits1/svelte-skills | Skill | 10 | 12d ago | MIT | A | 62 | Claude Code |
| imagegenopenai/codex | Skill | 133k | yesterday | Apache-2.0 | A | 113 | Codex |
| playwright-climicrosoft/playwright | Skill | 99k | yesterday | Apache-2.0 | A | 19 | Claude Code |
| local-ai-agentsmicrosoft/ai-agents-for-beginners | Skill | 79k | 4d ago | MIT | A | 200 | Claude Code, Codex |
| systematic-debuggingobra/superpowers | Skill | 313k | 3d ago | MIT | A | 21 | Claude Code |
| next-cache-components-adoptionvercel/next.js | Skill | 143k | yesterday | MIT | A | 95 | Claude Code |
| next-partial-prefetching-adoptionvercel/next.js | Skill | 143k | yesterday | MIT | A | 103 | Claude Code |