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.
npx skills add hassancs91/claude-youtube-editor --skill thumbnailgit clone --depth 1 https://github.com/hassancs91/claude-youtube-editorWrote 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.
[](https://agentmods.dev/skills/hassancs91/claude-youtube-editor/thumbnail)<a href="https://agentmods.dev/skills/hassancs91/claude-youtube-editor/thumbnail"><img src="https://agentmods.dev/badge/skills/hassancs91/claude-youtube-editor/thumbnail/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.
<a href="https://agentmods.dev/skills/hassancs91/claude-youtube-editor/thumbnail"><img src="https://agentmods.dev/badge/skills/hassancs91/claude-youtube-editor/thumbnail.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00141 | $0.02154 |
| Opus 5 | $0.00071 | $0.01077 |
| Sonnet 5 | $0.00028 | $0.00431 |
| Haiku 4.5 | $0.00014 | $0.00215 |
Grade A, and why
youtube-thumbnail 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 11d 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.
How it starts
The opening of the file, as written. The whole thing — 134 lines — stays where its author put it; the contents beside it link to each section on GitHub.
YouTube Thumbnail Generator
Turns a thumbnail concept into rendered, verified frames — with the style built from an element menu you pick from, not a fixed template. One number matters: CTR.
Division of labor: /packaging decides what to bet on (one fixed title, 3 distinct
thumbnail levers, honesty checks). This skill decides what the frame looks like and renders
it. Run standalone for iteration ("give me a new B"), or let packaging Stage 5 delegate here.
Both inherit two non-negotiables from packaging:
- Honesty guardrail — the frame must promise only what the video keeps.
- Loud-vs-calm — thumbnails are deliberately louder than
brand.md. Never tone down to match the in-video brand.
The baseline look (always on, never asked about)
Every render, regardless of selections: high contrast (deep darks OR clean brights, never
flat) · vibrant saturated color with one accent doing the work · clear focal hierarchy
(headline → hero object → face, three steps max) · big high-energy positive face from the
media/library/faces/ kit · premium, clickable finish — crisp edges, no clutter · every
text element perfectly spelled and razor sharp.
These came from a real before/after CTR comparison (the "Image 13" guide, 2026-08): the flat, low-contrast, no-hierarchy frame lost to the bold high-contrast hierarchical one ~4.4x on views. The axes are always-on; the decorations below are strictly opt-in.
The element menu (opt-in — this is what you ask about)
Exact prompt language for every element lives in references/style-elements.md. Summary:
| Element | What it is | Cost |
|---|---|---|
single-hook |
ONE text element, huge (word or number) | the default; cleanest |
tiered-headline |
small white italic context line + huge green grunge power line | +1 text block |
sticker |
tilted yellow badge, black caps, red underline, arrow to the hero | +1; ≤2 short words or it garbles |
checkstrip |
slim bottom strip, 3 green-check benefits | +3 micro-texts; busy fast |
brush-tag |
brush-stroke tag at strip end (e.g. WITH CLAUDE) | +1 |
results-fan |
fan/burst of result cards from the hero (pure imagery, no lettering) | busy-frame risk |
glow-burst |
neon energy + particles radiating from the hero | cheap, usually worth it |
real-logo |
pass the actual logo file as a --ref so it renders faithfully |
extra ref |
real-app-screen |
pass a real UI screenshot as a --ref for the on-screen app |
extra ref; micro-text caveat |
What ships with it
1 file 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.
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.
- 11d ago First seen · 134 lines · 141 tokens per session scan A 70cafb4a127e
youtube-thumbnail is a skill published in the GitHub repository hassancs91/claude-youtube-editor (303 stars, last pushed 23d ago), licensed MIT. It adds 141 tokens to every session and 2,154 once invoked, about $0.0007 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 2026-08-30.
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