what-iff: Skill for Claude Code

.agents/skills/playwright-component-testing/SKILL.md

playwright-component-testing is a skill for Claude Code, Codex from theimaginaryfoundation/what-iff. It costs 69 tokens per session (2,273 once invoked), scanned A, a copy of playwright-component-testing, Apache-2.0.

A method for testing React or Vue components in isolation with Playwright by rendering small example wrappers on a gallery page.

In plain words
What is it for?
Use it to create component stories, expose them through the gallery, and write Playwright tests for their behavior.
Why use it?
It avoids a separate component-test runner while still checking how an individual component renders and responds to user actions.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

This is theimaginaryfoundation/what-iff's own configuration. It tells Claude Code and Codex how to work on what-iff itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything what-iff configures →

Reuse

Borrowing it

Nothing to install: this file belongs to theimaginaryfoundation/what-iff. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/theimaginaryfoundation/what-iff/main/.agents/skills/playwright-component-testing/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/theimaginaryfoundation/what-iff

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for playwright-component-testing

README.md
[![agentmods](https://agentmods.dev/badge/skills/theimaginaryfoundation/what-iff/playwright-component-testing/github.svg)](https://agentmods.dev/skills/theimaginaryfoundation/what-iff/playwright-component-testing)
Your own site
<a href="https://agentmods.dev/skills/theimaginaryfoundation/what-iff/playwright-component-testing"><img src="https://agentmods.dev/badge/skills/theimaginaryfoundation/what-iff/playwright-component-testing/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.

agentmods 80×15 button for playwright-component-testing

Your own site · 80×15
<a href="https://agentmods.dev/skills/theimaginaryfoundation/what-iff/playwright-component-testing"><img src="https://agentmods.dev/badge/skills/theimaginaryfoundation/what-iff/playwright-component-testing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 69 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,273 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 100% copy Near-identical to another mod in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00069 $0.02273
Opus 5 $0.00034 $0.01137
Sonnet 5 $0.00014 $0.00455
Haiku 4.5 $0.00007 $0.00227

Measured yesterday against content hash 77bc6f8d1de5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

playwright-component-testing 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 yesterday.

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.

Origin

This is a copy

100% identical to playwright-component-testing — 15 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agents/skills/playwright-component-testing/SKILL.md · 144 lines

How it starts

The opening of the file, as written. The whole thing — 144 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Component Testing with Playwright

Test components with regular Playwright e2e tests against a small story gallery page hosted by the app's own dev server. No extra test runner, bundler integration or npm packages are required.

Concept

  • A story is a tiny wrapper component that embeds the component under test in one specific scenario: hard-coded props, mock data, providers, recorded callbacks. Stories live next to the component in *.story.tsx (or .ts/.jsx/.js/.vue) files; each named export is one story.
  • The gallery is a single page you implement to references/gallery-spec.md: it exposes window.mount(params) / window.unmount() that render a story — resolved from your story files (e.g. with import.meta.glob) — into #root. It is framework-specific and yours to own — there is no template to copy for it.
  • Tests are plain Playwright tests. The built-in mount(storyId, props?) fixture (from @playwright/test) drives the gallery's window.mount and returns a Locator for the gallery root (#root). Scope the queries from there — component.getByRole('button').click(), not component.click(). Nothing to scaffold for it.

Everything the component needs must be set up inside the story (it runs in the browser); everything the test asserts must be observable through the page (DOM, URL, network). Where the component takes callbacks, the story creates the state, provides the callbacks and records the state into a hidden form for the test to assert on. mount(id, props) passes plain serializable props to the story.

Setup workflow

  1. Detect the framework and bundler. React vs Vue decides the framework notes and example story to follow. Then:
    • App runs on Vite (has vite.config.*): the gallery is served by the existing dev server at /playwright/gallery/index.html — Vite serves any .html file under the project root, the app's plugins/aliases/CSS apply automatically, and vite build ignores it. No extra server needed.
    • Anything else (Next.js, webpack, no dev server): run a small standalone dev server (e.g. Vite) that serves the gallery page, and point baseURL at it. Requires vite and the framework plugin as devDependencies.
  2. Implement the gallery to references/gallery-spec.md: a page at <project>/playwright/gallery/ that renders the requested story into #root. Start from the worked example in the spec and the framework notes in references/react.md / references/vue.md. Keep story discovery (import.meta.glob) and the framework mount here — this is the only framework-specific glue, so keep it small. Import the app's global CSS the same way the app's own entry does.
  3. Configure Playwright — add to playwright.config.ts:

Read the full file on GitHub · 144 lines

Files

What ships with it

4 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.

Changes

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.

  1. yesterday First seen · 144 lines · 69 tokens per session scan A 77bc6f8d1de5

Subscribe to this mod's changes

playwright-component-testing is a skill published in the GitHub repository theimaginaryfoundation/what-iff (15 stars, last pushed yesterday), licensed Apache-2.0. It adds 69 tokens to every session and 2,273 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to playwright-component-testing, differing in 15 lines, and is treated as a copy.

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