Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/Thibaultbm/claude-seo-geonpx agentmods add skills/thibaultbm/claude-seo-geo/youtube-thumbnailWrote 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/thibaultbm/claude-seo-geo/youtube-thumbnail)<a href="https://agentmods.dev/skills/thibaultbm/claude-seo-geo/youtube-thumbnail"><img src="https://agentmods.dev/badge/skills/thibaultbm/claude-seo-geo/youtube-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/thibaultbm/claude-seo-geo/youtube-thumbnail"><img src="https://agentmods.dev/badge/skills/thibaultbm/claude-seo-geo/youtube-thumbnail.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00175 | $0.02153 |
| Opus 5.5 | $0.00070 | $0.00861 |
| Sonnet 5.5 | $0.00035 | $0.00431 |
| Haiku 4.5 | $0.00017 | $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 5d 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 — 111 lines — stays where its author put it; the contents beside it link to each section on GitHub.
YouTube Thumbnail: Readable at Phone Size, True to the Video
Most viewers see a thumbnail at the size of a stamp, next to a dozen others. A thumbnail works when, at that size, one face or one image and two to six words make the promise obvious, in the brand's colors, and when the video keeps that promise. The automatic frame YouTube proposes is never accepted.
Company knowledge first (Obsidian)
If the working environment contains an Obsidian vault or any local knowledge base (a folder of .md notes, often with a .obsidian directory), read the relevant notes before acting: the brand guidelines (colors with their hex codes, fonts, logo files), the reference photos of the people who appear on camera, and past thumbnails with their click-through rates. At the end, record the validated template and any new rule in the note that owns them.
When to use this skill
| The user wants | Use this skill? | Where it belongs |
|---|---|---|
| A thumbnail, a template, or an image prompt for one | Yes | here |
| To choose the words on the thumbnail | Partly | the hook comes from youtube-title, its layout is here |
| The title or the description | No | youtube-title, youtube-description |
| Branded visuals for other platforms | No | social-amplification |
Fixed specifications
- 1280x720 pixels, 16:9, JPEG or PNG, under 2 MB (YouTube's limit for custom thumbnails; the account must be verified to upload one).
- One thumbnail per language: the text is rewritten in each language, never left in the original.
- Name the file like the video (
<video-file-name>.jpg) and store all thumbnails in one folder, so any video's thumbnail can be found and reused. - Keep the bottom right corner free: YouTube prints the duration there.
- Readability test: shrink the thumbnail to 320x180, then to 168x94 (suggested videos on desktop). The main text must stay readable at 320x180 and the subject recognizable at 168x94. If not, cut words or enlarge them; never shrink the text to fit more.
What ships with it
3 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.
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.
- 5d ago First seen · 111 lines · 175 tokens per session scan A 388f6e1960fd
youtube-thumbnail is a skill published in the GitHub repository Thibaultbm/claude-seo-geo (18 stars, last pushed today), licensed MIT. It adds 175 tokens to every session and 2,153 once invoked, about $0.0007 per session on Opus 5.5. 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 2026-11-03.
youtube-thumbnail compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| youtube-thumbnailThibaultbm/claude-seo-geo | Skill | 18 | today | MIT | A | 175 | Claude Code |
| geo-audittechhorizonlabs/thl-open | Skill | 19 | 1mo ago | MIT | A | 60 | Claude Code |
| geotechhorizonlabs/thl-open | Skill | 19 | 1mo ago | MIT | A | 139 | Claude Code |
| found-by-aitechhorizonlabs/thl-open | Skill | 19 | 1mo ago | MIT | A | 67 | Claude Code |
| geo-brand-mentionstechhorizonlabs/thl-open | Skill | 19 | 1mo ago | MIT | A | 49 | Claude Code |
| geo-llmstxttechhorizonlabs/thl-open | Skill | 19 | 1mo ago | MIT | A | 46 | Claude Code |
| agent-readiness-scantechhorizonlabs/thl-open | Skill | 19 | 1mo ago | MIT | A | 79 | Claude Code |