what-iff: Skill for Claude Code

.agents/skills/playwright-version/SKILL.md

playwright-version is a skill for Claude Code, Codex from theimaginaryfoundation/what-iff. It costs 111 tokens per session (1,240 once invoked), scanned A, original, Apache-2.0.

A procedure for changing the Playwright version while keeping the browser version and committed visual screenshots aligned.

In plain words
What is it for?
Use it when upgrading Playwright, changing the CI browser image, or investigating visual-test differences after a dependency update.
Why use it?
Different browser versions can change text rendering and image pixels, causing visual tests to fail even when the code is correct.

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-version/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-version

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/theimaginaryfoundation/what-iff/playwright-version"><img src="https://agentmods.dev/badge/skills/theimaginaryfoundation/what-iff/playwright-version.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 111 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,240 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 original No closer match found 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 $0.00111 $0.01240
Opus 5 $0.00056 $0.00620
Sonnet 5 $0.00022 $0.00248
Haiku 4.5 $0.00011 $0.00124

Measured yesterday against content hash eeb620c25824, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

playwright-version 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.

.agents/skills/playwright-version/SKILL.md · 99 lines

How it starts

The opening of the file, as written. The whole thing — 99 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Playwright version: one source of truth

web/app/package.jsondevDependencies["@playwright/test"] is the source of truth. It is pinned exactly1.62.1, never ^1.62.1.

Everything else derives from it through one resolver:

web/app/e2e/scripts/playwright-version.sh   # prints e.g. 1.62.1

Its only consumer now is scripts/ci-image.sh, which folds the resolved version into the CI base image's tag (see the ci-image-version skill for that layer). Everything that used to read playwright-version.sh directly — e2e/scripts/visual-docker.sh, .github/workflows/e2e-mock.yml's version job — now calls scripts/ci-image.sh e2e instead, so both resolve the same baked image ref rather than each deriving a bare Playwright tag on its own.

Why exact, and why this matters more than a normal dependency

The PNGs under e2e/tests/visual/**-snapshots/ were rasterized by the browsers bundled inside one specific CI base image (docker/ci/Dockerfile's e2e target, tagged ...:e2e-pwX.Y.Z-<digest>). Compare them using a different image and you are checking against a renderer that never produced them — font hinting and antialiasing shift, and the failures read as real UI regressions. Version skew here does not break the build honestly; it produces plausible, wrong diffs.

A range makes that skew invisible: npm install or a bot can move the installed version inside ^1.62.1 while the image tags stay literal. Exact pinning makes the version a fact rather than a constraint, which is what lets an image tag be derived from it at all.

playwright-version.sh enforces both halves — it refuses a range, and it refuses a node_modules that disagrees with package.json.

Upgrading

  1. Bump the pin in web/app/package.json to the new exact version, then npm install so the lockfile follows.
  2. Confirm the resolver agrees:
    web/app/e2e/scripts/playwright-version.sh
    
    A mismatch error here means the install did not take.
  3. The CI base image updates itself. scripts/ci-image.sh resolves the version through this same script and folds it into the image tag it computes (ghcr.io/theimaginaryfoundation/what-iff-ci:e2e-pw<version>-<hash>), so visual-docker.sh and the ci-image.yml/e2e-mock.yml workflows all pick up the new Playwright base image automatically — nothing to edit by hand. If the OS suffix Playwright publishes under has moved on (Jammy → Noble), that's the one thing still hardcoded, in docker/ci/Dockerfile's FROM mcr.microsoft.com/playwright:v${PLAYWRIGHT_VERSION}-noble line.
  4. Regenerate the visual baselines in the new image — this is the step that is easy to skip and expensive to skip:
    cd web/app && npm run e2e:mock-llm:visual:docker:update
    
  5. Review the regenerated PNGs before committing. A version bump legitimately shifts rendering by a pixel or two; a real UI change looks different. If you cannot tell them apart, that is a signal to bump the version in its own commit, separate from any UI work, so the diff has one cause.
  6. Run the visual specs once more without :update to confirm they now pass against the baselines you just made.

Read the full file on GitHub · 99 lines

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 · 99 lines · 111 tokens per session scan A eeb620c25824

Subscribe to this mod's changes

playwright-version is a skill published in the GitHub repository theimaginaryfoundation/what-iff (15 stars, last pushed yesterday), licensed Apache-2.0. It adds 111 tokens to every session and 1,240 once invoked, about $0.0006 per session on Opus 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 2026-09-09.

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