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repo-social-preview

repo-social-preview is a skill for Claude Code from bestdeejay-design/agent-skills. It costs 105 tokens per session (1,181 once invoked), scanned A, original, MIT.

A specialist audit for the deeper technical causes of slow websites, including network responses, browser loading, built files, and Core Web Vitals. Core Web Vitals are Google’s measures of loading speed, responsiveness, and layout stability.

In plain words
What is it for?
Use it to inspect response headers, protocols, transfer timing, asset sizes, JavaScript and CSS bundles, resource hints, and real Chrome loading metrics.
Why use it?
It exposes performance issues that a basic page audit may miss, such as oversized bundles, slow server responses, blocking files, and missing compression or caching.

Skill for Claude Code

Written for Claude Code: when-to-use in frontmatter.

not rated 6repo +1 changed today A scan 105 tokens original MIT

Good fit Use it to inspect response headers, protocols, transfer timing, asset sizes, JavaScript and CSS bundles, resource hints, and real Chrome loading metrics.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/bestdeejay-design/agent-skills/repo-social-preview
View source ↗ bestdeejay-design/agent-skills bestdeejay-design.github.io
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 bestdeejay-design/agent-skills --skill repo-social-preview
Clone the repo
git clone --depth 1 https://github.com/bestdeejay-design/agent-skills

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 repo-social-preview

README.md
[![agentmods](https://agentmods.dev/badge/skills/bestdeejay-design/agent-skills/repo-social-preview/github.svg)](https://agentmods.dev/skills/bestdeejay-design/agent-skills/repo-social-preview)
Your own site
<a href="https://agentmods.dev/skills/bestdeejay-design/agent-skills/repo-social-preview"><img src="https://agentmods.dev/badge/skills/bestdeejay-design/agent-skills/repo-social-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 repo-social-preview

Your own site · 80×15
<a href="https://agentmods.dev/skills/bestdeejay-design/agent-skills/repo-social-preview"><img src="https://agentmods.dev/badge/skills/bestdeejay-design/agent-skills/repo-social-preview.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 105 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,181 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 $0.00105 $0.01181
Opus 5 $0.00053 $0.00590
Sonnet 5 $0.00021 $0.00236
Haiku 4.5 $0.00011 $0.00118

Measured today against content hash 4ee6cdfc446b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

repo-social-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 today.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/render_social_preview.py), 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.

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.

skills/repo-social-preview/SKILL.md · 87 lines

How it starts

The opening of the file, as written. The whole thing — 87 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Repo Social Preview — og:image as a typeset hero section

The social preview is a piece of web design, not a generated raster. Lay out a clean hero section in HTML/CSS, render it with headless Chrome, upload the PNG.

Hard rules

  1. Typeset HTML — never compose pixels. No Pillow drawing, no self-made SVG shapes, no site screenshots. The deliverable is a standalone hero.html. Existing assets from the site (logo URL, brand fonts) may be referenced; do not draw new ones.
  2. Hero only. No header, nav, footer, badges, cookie bars. One full-bleed 1280×640 hero section: headline, optional subline/CTA, brand background.
  3. 40pt padding on all sides (padding: 40pt). This is the GitHub crop-safe hint: essential text and logos must stay inside it — share previews crop edges.
  4. Site is the source of truth. If the repo has a website with a hero section, re-typeset that hero: its headline, subline, palette, typeface. Do not invent a different design; do not embed an iframe or screenshot of it.
  5. Front-end quality bar. Build the markup per the frontend skill: real typography scale, brand tokens as CSS variables, no layout hacks.

Workflow

  1. Collect source material
    • Website exists → fetch it, extract the hero: headline, subline, CTA text, colors, fonts, logo URL.
    • No website → build from README/description: repo name + one-line value prop.
  2. Lay out hero.html (standalone file, fixed 1280×640 viewport): 
    <!doctype html>
<html><head><meta charset="utf-8">
<link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=Inter:wght@400;600;800">
<style>
  :root { --brand-a:#F64A8A; --brand-b:#0ABAB5; --ink:#1A1A1A; }
  * { margin:0 }
  body { width:1280px; height:640px; overflow:hidden }
  .hero { width:100%; height:100%; box-sizing:border-box; padding:40pt;
          display:flex; flex-direction:column; justify-content:center; gap:16pt;
          background:linear-gradient(90deg, var(--brand-a) 50%, var(--brand-b) 50%); }
</style></head>
<body><section class="hero">…</section></body></html>
    Solid background preferred over transparency; hard color stops are fine, keep text contrast ≥ WCAG AA.
  3. Render to PNG: 
    python3 scripts/render_social_preview.py hero.html --out og.png
    Headless Chrome renders real web layout pixel-perfectly (webfonts included).
  4. Verify: exactly 1280×640, < 1 MB, nothing clipped at the edges, text readable at thumbnail size. Re-render if any check fails.
  5. Upload manually: Settings → Social preview → Edit → Upload (no API).

Read the full file on GitHub · 87 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. today Changed · +8 lines 4ee6cdfc446b
  2. 12d ago First seen · 79 lines · 105 tokens per session scan A 489328a889b0

Subscribe to this mod's changes

repo-social-preview is a skill published in the GitHub repository bestdeejay-design/agent-skills (6 stars, last pushed yesterday), licensed MIT. It adds 105 tokens to every session and 1,181 once invoked, about $0.0005 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 2026-08-31.

Creative and mediaDesign and UXProductivityPythonai-agentsautomationopencodepresentation-generator
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