tingly-box: Skill for Claude Code

.claude/skills/ui-preview/SKILL.md

ui-preview is a skill for Claude Code from tingly-dev/tingly-box. It costs 96 tokens per session (2,009 once invoked), scanned C, original, MPL-2.0.

A tool guide for taking screenshots of a locally running web interface with Chrome controlled by code. It is set up for the tingly-box frontend in mock mode, so the interface can be viewed without a real browser session.

In plain words
What is it for?
Installing the frontend dependencies, starting the mock interface, capturing screenshots, and visually checking pages or components.
Why use it?
It provides visual evidence that a frontend change looks correct and helps catch layout problems that code or automated tests may miss.

Skill for Claude Code

Written for Claude Code: installed under .claude/. Also seen: mentions Claude Code; mentions Codex.

This is tingly-dev/tingly-box's own configuration. It tells Claude Code how to work on tingly-box 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 tingly-box configures →

Reuse

Borrowing it

Nothing to install: this file belongs to tingly-dev/tingly-box. 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/tingly-dev/tingly-box/main/.claude/skills/ui-preview/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/tingly-dev/tingly-box

Made for: Claude Code.

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 ui-preview

README.md
[![agentmods](https://agentmods.dev/badge/skills/tingly-dev/tingly-box/ui-preview/github.svg)](https://agentmods.dev/skills/tingly-dev/tingly-box/ui-preview)
Your own site
<a href="https://agentmods.dev/skills/tingly-dev/tingly-box/ui-preview"><img src="https://agentmods.dev/badge/skills/tingly-dev/tingly-box/ui-preview/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 ui-preview

Your own site · 80×15
<a href="https://agentmods.dev/skills/tingly-dev/tingly-box/ui-preview"><img src="https://agentmods.dev/badge/skills/tingly-dev/tingly-box/ui-preview.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 96 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,009 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 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 $0.00096 $0.02009
Opus 5.5 $0.00038 $0.00804
Sonnet 5.5 $0.00019 $0.00402
Haiku 4.5 $0.00010 $0.00201

Measured 27d ago against content hash 9b50d18e9c3e, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade C, and why

ui-preview scanned grade C with 2 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 27d ago.

The scan reads SKILL.md. This mod also ships 4 executable files (docs-screenshots.mjs, regression-credentials.mjs, scenario-routing-graph.mjs, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Recursive force deletehighDestructive command

rm -rf with a variable or a broad path is one typo away from removing the wrong tree.

# polluted by npm — wipe it first with `rm -rf node_modules` if you suspect that).

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -fsSL -o chrome.zip \
.claude/skills/ui-preview/SKILL.md · 170 lines

How it starts

The opening of the file, as written. The whole thing — 170 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Headless UI preview (Playwright + Chrome for Testing)

Designed for the remote-execution container where:

  • cdn.playwright.dev / dl.google.com are blocked — use Chrome for Testing via storage.googleapis.com.
  • Ubuntu's chromium-browser is a snap stub and won't run.
  • MCP servers can't be registered mid-session — use Playwright's Node API directly.

Setup (run once per fresh container)

⚠️ This project uses pnpm (frontend/pnpm-lock.yaml is the source of truth). Do NOT run npm i here — npm ignores the pnpm lockfile and re-resolves transitive deps, which pulls broken versions (e.g. [email protected] vs the pinned 1.46.1) that crash the whole SPA at load. See Troubleshooting below.

playwright is already a committed devDependency in frontend/package.json, so a plain install provides it — no ad-hoc add/revert needed. @emotion/react / @emotion/styled are likewise already declared.

# 1. Install deps from the lockfile (also fixes a node_modules previously
#    polluted by npm — wipe it first with `rm -rf node_modules` if you suspect that).
cd frontend
pnpm install --frozen-lockfile

# 2. Download Chrome for Testing (Playwright's own Chromium download is blocked)
mkdir -p /tmp/chrome && cd /tmp/chrome
curl -fsSL -o chrome.zip \
  "https://storage.googleapis.com/chrome-for-testing-public/148.0.7778.96/linux64/chrome-linux64.zip"
unzip -q chrome.zip          # → /tmp/chrome/chrome-linux64/chrome

Do NOT modify frontend/package.json / frontend/pnpm-lock.yaml for tooling anymore — everything needed is already committed. If a previous session left them dirty (or npm polluted the tree), reset with:

cd <repo> && git checkout -- frontend/package.json frontend/pnpm-lock.yaml
pnpm -C frontend install --frozen-lockfile

Dev server

cd frontend
USE_MOCK=true node_modules/.bin/vite --mode mock --port 3000 &
until curl -fs http://localhost:3000 >/dev/null; do sleep 1; done

USE_MOCK=true must be a shell env var (read by vite.config.ts before .env.mock).

Read the full file on GitHub · 170 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. 27d ago Changed · +20 lines 9b50d18e9c3e
  2. 1mo ago Changed c66948c38e22
  3. 1mo ago Changed · +15 lines 61e97b50897c
  4. 1mo ago First seen · 135 lines · 96 tokens per session scan C 5821600675b4

Subscribe to this mod's changes

ui-preview is a skill published in the GitHub repository tingly-dev/tingly-box (367 stars, last pushed today), licensed MPL-2.0. It adds 96 tokens to every session and 2,009 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it C with 2 findings (recursive force delete, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.