pn-html-preview

pn-html-preview is a skill for Cursor from perniemann/pnCore. It costs 29 tokens per session (464 once invoked), scanned A, original, MIT.

A procedure for saving a self-contained HTML page to a file and opening it in a browser for visual checking.

In plain words
What is it for?
Use it to preview landing pages, component demos, and HTML email prototypes, with optional screenshot evidence.
Why use it?
It provides a quick way to inspect a static page or prototype without setting up a larger application.

Skill for Cursor

Written for Cursor: shipped in a Cursor plugin.

Part of the pn-core plugin — 133 skills, 19 commands, 9 agents, 1 MCP server shipped together

Good fit Use it to preview landing pages, component demos, and HTML email prototypes, with optional screenshot evidence.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/perniemann/pncore/pn-html-preview
Install

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.

Any agent
npx skills add perniemann/pnCore --skill pn-html-preview
Clone the repo
git clone --depth 1 https://github.com/perniemann/pnCore

Made for: Cursor.

Or install pn-core, the plugin that ships this one along with the rest of its 133 skills, 19 commands, 9 agents, 1 MCP server.

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 pn-html-preview

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/perniemann/pncore/pn-html-preview"><img src="https://agentmods.dev/badge/skills/perniemann/pncore/pn-html-preview.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 464 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 $0.00029 $0.00464
Opus 5 $0.00015 $0.00232
Sonnet 5 $0.00006 $0.00093
Haiku 4.5 $0.00003 $0.00046

Measured 7d ago against content hash 23b144e80ea0, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

pn-html-preview 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 7d 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.

packages/pn-core-mcp/content/skills/frontend/pn-html-preview/SKILL.md · 45 lines

What it actually says

HTML Preview

When to use

  • Static landing page, component demo, or HTML email prototype (saved as .html for visual check).
  • Any request where the output is "one HTML file" and distinctiveness matters.
  • After pn-design or pn-frontend-design when stack is vanilla HTML.

Instructions

1. Obtain HTML

If not already in chat: ask the user to paste the ```html block or point to a file.

Extract the first fenced html block (or use the file contents if they gave a path). Strip the fence lines only; keep <!DOCTYPE html> through closing </html>.

2. Save

  • Default directory: html_outputs/ at project root (create if missing).
  • Filename: html_outputs/YYYYMMDD_HHMMSS_preview.html or a user-provided name (sanitized, .html only).
  • Write UTF-8. Do not overwrite without confirmation.

3. Open and verify

  • Open the file in the system default browser (e.g. xdg-open, open, or start with file:// absolute path). If the environment blocks browser launch, print the absolute path and instruct the user to open it locally.
  • Quick pass: layout, typography, color, motion (if any), and reduced-motion behavior if media queries exist.

4. Evidence (optional)

For high-stakes UI, run pn-evidence-qa or capture a screenshot after load and attach to the summary.

5. Summary

Output: file path, how to reopen, and any issues found in the browser pass.

Guardrails

  • Security: Do not fetch remote scripts into the file unless the user asked; prefer self-contained snippets for previews.
  • Parser: If the model did not use a ```html fence, ask for a single fenced block — downstream tooling and this skill assume that format.
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. 7d ago First seen · 45 lines · 29 tokens per session scan A 23b144e80ea0

Subscribe to this mod's changes

pn-html-preview is a skill published in the GitHub repository perniemann/pnCore (0 stars, last pushed 4d ago), licensed MIT. It adds 29 tokens to every session and 464 once invoked, about $0.0001 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 2026-09-03.

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