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Agent skill

Penguin Harness Manual Test

by Prism-Shadow in Prism-Shadow/penguin-harness

A skill your agent uses when standing PenguinHarness up to try a change by hand — launching the Web App, the desktop shell, the landing page, the docs site or the component gallery to click through…

Apache-2.0Auto-check passedFrontend & Design

Install Penguin Harness Manual Test

skills CLI
$ npx skills add Prism-Shadow/penguin-harness --skill penguin-harness-manual-test -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install Prism-Shadow/penguin-harness penguin-harness-manual-test --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/Prism-Shadow/penguin-harness.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/penguin-harness-manual-test .claude/skills/penguin-harness-manual-test && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
penguin-harness-manual-test
GitHub stars
2.5k
Token cost
~1.3k tokens
SKILL.md length
734 words
Files
1
Skills in repo
30
Repo updated
First seen
Licence
Apache-2.0

At a glance

A skill your agent uses when standing PenguinHarness up to try a change by hand — launching the Web App, the desktop shell, the landing page, the docs site or the component gallery to click through…

  • Standing PenguinHarness up to try a change by hand — launching the Web App
  • SKILL.md covers Entry points, Four ways a working setup…, One instance at a time and PENGUIN_HOME, plus 3 more sections
  • Calls pnpm and curl; needs PENGUIN_SEED_ADMIN_PASSWORD
  • The desktop shell

What it does

Penguin Harness Manual Test is an agent skill from Prism-Shadow/penguin-harness. Use when standing PenguinHarness up to try a change by hand — launching the Web App, the desktop shell, the landing page, the docs site or the component gallery to click through it, screenshot it, or reproduce a report. Covers the dev entry points and their ports, which data root each writes to, and the four ways a healthy setup looks broken.

Its SKILL.md is about 1.3k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Frontend & Design, covering Landing pages and Static sites and blogs. It works with pnpm. The repository describes itself as: 🐧 Unified and Stable RSI Platform. The licence is Apache-2.0.

When your agent uses it

  • Standing PenguinHarness up to try a change by hand — launching the Web App
  • The desktop shell
  • The landing page
  • The component gallery to click through it

Example prompts

  • “/penguin-harness-manual-test”

What it can do on your machine

Read from SKILL.md and the folder at commit aedeac7. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    Shell commands in SKILL.md call:

    • pnpm
    • curl

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md. Its commands use pnpm and curl, which can reach the network depending on how they are called.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names these keys or tokens, usually read from environment variables:

    • PENGUIN_SEED_ADMIN_PASSWORD

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Penguin Harness Manual Test loads about 1.3k tokens when it runs. Until then it costs about 93 tokens; SKILL.md has 734 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~93
When it runs · the whole SKILL.md, loaded when a task matches
~1.3k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from Prism-Shadow/penguin-harness at commit aedeac7, republished under its Apache-2.0 licence (© Prism-Shadow). 734 words, ~1,324 tokens.

Download SKILL.mdSave it as .claude/skills/penguin-harness-manual-test/SKILL.md (or your agent's skills folder).
name
penguin-harness-manual-test
description
Use when standing PenguinHarness up to try a change by hand — launching the Web App, the desktop shell, the landing page, the docs site or the component gallery to click through it, screenshot it, or reproduce a report. Covers the dev entry points and their ports, which data root each writes to, and the four ways a healthy setup looks broken.

Standing PenguinHarness up to test by hand

Node >= 24. dev:* runs dev-prebuild.mjs first (keeps pnpm install current, prebuilds workspace deps); pnpm desktop runs a full pnpm -r build, so it is slow to start.

Entry points

CommandOpenData root
pnpm devhttp://localhost:7365~/.penguin/dev-data
pnpm desktopits own window~/.penguin/dev-data
installed app, launched with --devits own window~/.penguin/dev-data
pnpm dev:landinghttp://localhost:7366none (static)
pnpm dev:docshttp://localhost:7367none (static)
pnpm dev:galleryhttp://localhost:7372none (static)

Other fixed ports (packages/core/src/internal/ports.ts): 7364 installed server, 7368 dev backend, 7369 pnpm penguin web (data root ~/.penguin/dev-data-cli — its own, so it can serve while an Agent it hosts runs pnpm dev; the lock is per root). On a shared box, ss -tln before assuming one is free; PORT= inline moves it. The gallery's port is strict — a busy 7372 fails instead of drifting, because quoted gallery links and pnpm --filter @prismshadow/penguin-ui-gallery shots name it.

The user's installed app, server and CLI all use ~/.penguin/data — their real Agents, Sessions and keys. Never point a dev run there. Both surfaces print the root they took (Data root: …, [shell] dev instance … on data root …); read it rather than assume.

Four ways a working setup looks broken

7368 shows a stale app. The dev backend also serves packages/web/dist — the last pnpm -r build, not what Vite is serving. Screenshot 7365, never 7368.

curl returns 502 but the server is fine. A shell http_proxy routes loopback through the proxy. Use curl --noproxy '*'. Browsers and the server itself are unaffected.

/api on 127.0.0.1 returns 401. That address is reserved as the Workspace-preview host. Use localhost.

The server exits 3 saying the data root is in use. Another instance — usually the user's own desktop app — holds <root>/server.lock. The lock is per root, not per port, so PORT= will not get past it. Use a different root; do not kill their process.

One instance at a time

Only one local dev instance runs at a time, counting every agent's. A separate root gets you past the lock but not past the browser: cookies and the admin claim are shared across instances, so bringing a second one up corrupts the first's session state. Stop the previous PR's instance before starting the next.

The slot belongs to the task that genuinely needs a running server — watching a live stream, driving a real tool call. The rest verify statically: for an icon-legibility or spacing question a throwaway HTML render shows the same pixels at a fraction of the cost.

Show full SKILL.md (322 more words)Show less

PENGUIN_HOME

Never export it. scripts/run-with-env.mjs applies each VAR=value only when unset, so an exported value silently redirects every dev script — an exported ~/.penguin/data puts pnpm dev on the user's real data, where the lock is already held. It now names any default the environment displaced before running, so read that line if it appears.

When you need your own root, prefix the one command:

sh
PENGUIN_HOME=~/.penguin/dev-data-<topic> pnpm dev

Unset it rather than blanking it: run-with-env reads empty as unset, but resolveRoot() uses ?? and takes an empty string literally.

Signing in

A fresh root seeds admin with a random penguin-<4 digits> password, printed once at startup. PENGUIN_SEED_ADMIN_PASSWORD pins it, which is how the e2e harness logs in.

The first-login link the server prints is the user's to open, not yours — no curl, no browser, no headless fetch. It redeems into whichever cookie jar made the request, and the desktop shell's variant is spent on first use, so following it can lock the user out of their own instance. Hand them the URL and wait. A restart prints a fresh one, so it is recoverable, but only by interrupting them. Being blocked here is an acceptable outcome: report how far you got and what stayed unverified rather than guessing.

Under pnpm dev the printed link carries the wrong port. index.ts builds it as http://<host>:<port>/api/auth/claim?token=… from the server's own listener, which in dev is the backend on 7368 — but the App is Vite on 7365, and Vite is what serves the page the redirect lands on. Swap the port before handing the link over: http://localhost:7365/api/auth/claim?token=…. The token is the same either way; only the origin that ends up holding the cookie changes.

Editing while it runs

Changes to core or skills do not reach a running dev server — web/server consume snapshot copies that re-sync only when that package's build runs. Restart pnpm dev.

When you are done

Stop what you started. Leave anything the user was already running alone.

© Prism-Shadow, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in .agents/skills/penguin-harness-manual-test of Prism-Shadow/penguin-harness.

Open the folder on GitHubat commit aedeac7

Compare with similar skills

Penguin Harness Manual Test next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Penguin Harness Manual Test compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Penguin Harness Manual Test this skillPrism-Shadow/penguin-harness2.5k—~1.3kAutomated safety check: PassApache-2.0
Create Docsvictorgarciaesgi/nuxt-typed-router4132 repos~2.8kAutomated safety check: PassMIT
Kill AI Slopyetone/kill-ai-slop1.3k—~1.4kAutomated safety check: PassApache-2.0
Static Sitesbionic-gpt/bionic-gpt2.4k—~920Automated safety check: PassApache-2.0
Auteuragiwhitelist/auteur1k—~5kAutomated safety check: PassMIT
SEO Landingaleksandr-alhoff/seo-landing165—~3.4kAutomated safety check: PassMIT

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Works with

Categories

Questions about Penguin Harness Manual Test

What does Penguin Harness Manual Test do?

A skill your agent uses when standing PenguinHarness up to try a change by hand — launching the Web App, the desktop shell, the landing page, the docs site or the component gallery to click through…. Penguin Harness Manual Test is an agent skill from Prism-Shadow/penguin-harness. Use when standing PenguinHarness up to try a change by hand — launching the Web App, the desktop shell, the landing page, the docs site or the component gallery to click through it, screenshot it, or reproduce a report.

When should I use Penguin Harness Manual Test?

Penguin Harness Manual Test fits situations like: standing PenguinHarness up to try a change by hand — launching the Web App; the desktop shell; the landing page; the component gallery to click through it.

How do I install Penguin Harness Manual Test in Claude Code?

Run `npx skills add Prism-Shadow/penguin-harness --skill penguin-harness-manual-test -a claude-code`. Or copy the skill folder (.agents/skills/penguin-harness-manual-test in Prism-Shadow/penguin-harness) into .claude/skills/penguin-harness-manual-test in your project. Claude Code loads it when a task matches its description.

How do I install Penguin Harness Manual Test in Codex?

Run `npx skills add Prism-Shadow/penguin-harness --skill penguin-harness-manual-test -a codex`. Or copy the skill folder (.agents/skills/penguin-harness-manual-test in Prism-Shadow/penguin-harness) into .agents/skills/penguin-harness-manual-test in your project. Codex loads it when a task matches its description.

Can I use Penguin Harness Manual Test in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add Prism-Shadow/penguin-harness --skill penguin-harness-manual-test -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/penguin-harness-manual-test, .gemini/skills/penguin-harness-manual-test, .github/skills/penguin-harness-manual-test and .opencode/skills/penguin-harness-manual-test in your project.

What does Penguin Harness Manual Test need to run?

Going by SKILL.md and its folder, Penguin Harness Manual Test needs the command-line tools its instructions call (pnpm and curl) and credentials named PENGUIN_SEED_ADMIN_PASSWORD.

Does Penguin Harness Manual Test access the network?

SKILL.md contains no URLs. Its commands use curl, which can reach the network depending on how they are called. This is read from the text; nothing was executed.

Is Penguin Harness Manual Test safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Penguin Harness Manual Test use?

Penguin Harness Manual Test is published under the Apache-2.0 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Penguin Harness Manual Test use?

About 1.3k tokens (SKILL.md is roughly 5.3k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Penguin Harness Manual Test?

Skills that share tags, products or a category with Penguin Harness Manual Test: Create Docs (victorgarciaesgi/nuxt-typed-router, 413 stars), Kill AI Slop (yetone/kill-ai-slop, 1.3k stars), Static Sites (bionic-gpt/bionic-gpt, 2.4k stars) and Auteur (agiwhitelist/auteur, 1k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Penguin Harness Manual Test?

Prism-Shadow (a GitHub organization) maintains it in Prism-Shadow/penguin-harness, which has 2,475 GitHub stars. The repository holds 30 skills in this directory. The repository was last updated on October 11, 2026.

Source: Prism-Shadow/penguin-harness on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.