youtube-seo-thumbnail

youtube-seo-thumbnail is a skill for Claude Code from deeployCO/youtube-seo-skills. It costs 65 tokens per session (1,851 once invoked), scanned A, original, MIT.

A skill for reviewing YouTube thumbnails using image analysis, comparisons with search results, layout principles, and planning for YouTube's Test & Compare feature.

In plain words
What is it for?
Use it to assess faces and emotions, colors, contrast, text visibility, mobile readability, composition, and similarity to competing thumbnails, then plan improvements.
Why use it?
It helps identify why a thumbnail may be hard to notice, read, or distinguish from competing videos, especially at small sizes.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Good fit Use it to assess faces and emotions, colors, contrast, text visibility, mobile readability, composition, and similarity to competing thumbnails, then plan improvements.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/deeployco/youtube-seo-skills/youtube-seo-thumbnail
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 deeployCO/youtube-seo-skills --skill youtube-seo-thumbnail
Clone the repo
git clone --depth 1 https://github.com/deeployCO/youtube-seo-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 youtube-seo-thumbnail

README.md
[![agentmods](https://agentmods.dev/badge/skills/deeployco/youtube-seo-skills/youtube-seo-thumbnail/github.svg)](https://agentmods.dev/skills/deeployco/youtube-seo-skills/youtube-seo-thumbnail)
Your own site
<a href="https://agentmods.dev/skills/deeployco/youtube-seo-skills/youtube-seo-thumbnail"><img src="https://agentmods.dev/badge/skills/deeployco/youtube-seo-skills/youtube-seo-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.

agentmods 80×15 button for youtube-seo-thumbnail

Your own site · 80×15
<a href="https://agentmods.dev/skills/deeployco/youtube-seo-skills/youtube-seo-thumbnail"><img src="https://agentmods.dev/badge/skills/deeployco/youtube-seo-skills/youtube-seo-thumbnail.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 65 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,851 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 $0.00065 $0.01851
Opus 5 $0.00032 $0.00925
Sonnet 5 $0.00013 $0.00370
Haiku 4.5 $0.00006 $0.00185

Measured 12d ago against content hash 16edf3b140e0, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

youtube-seo-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 12d 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.

youtube-seo-thumbnail/SKILL.md · 213 lines

How it starts

The opening of the file, as written. The whole thing — 213 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Thumbnail Analysis (Advanced)

Diagnose CTR potential quantitatively when possible, qualitatively when not. Thumbnail is the single biggest pre-click lever after title.

Data Collection

  1. Source thumbnail: download the maxres (maxresdefault.jpg) from https://i.ytimg.com/vi/{VIDEO_ID}/maxresdefault.jpg, fall back to hqdefault.jpg if missing
  2. SERP grid: fetch the top 12 YouTube results for the primary keyword, download each thumbnail, build a 4x3 contact sheet
  3. Computer-vision pass via scripts/analyze_thumbnail.py:
    • OpenCV face detection (count, bbox, size %)
    • MediaPipe face-mesh for emotion inference (or DeepFace fallback)
    • Color histogram (HSV) — dominant 3 colors
    • Contrast score (stddev of luminance)
    • Text region detection (EAST or Tesseract) — estimated word count and coverage %
    • CLIP embedding (ViT-B/32) for similarity scoring vs SERP grid
  4. Mobile preview: resize to 120x68, 246x138, 480x270 and inspect legibility manually

Analysis Dimensions

1. Technical

  • Resolution 1280x720, 16:9, max 2MB
  • Format JPG / PNG
  • Safe area: no critical content in bottom-right (duration overlay ~6% of area) or top-right (menu dots)

2. Legibility at small sizes (binding constraint)

At 120x68:

  • Subject identifiable? (pass/fail)
  • Text readable? (pass/fail)
  • Emotion readable? (pass/fail)

If any fail → critical issue. Most thumbnails designed on a desktop monitor at 500px+ fail at 120px.

3. Composition — Gestalt principles

  • Figure-ground separation: subject clearly separated from background (rim light, cutout, color contrast, background blur)
  • Closure: viewer's brain completes an implied shape or story — works against scroll blindness
  • Continuity: eye travels in a designed path (eye direction of face, arrow of object, gradient)
  • Similarity/proximity: elements that belong together are grouped
  • Rule of thirds: focal point at intersections, not dead-center
  • Depth: foreground / midground / background create dimensionality
  • Negative space: enough breathing room for the focal point to pop at small sizes

Read the full file on GitHub · 213 lines

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. 12d ago First seen · 213 lines · 65 tokens per session scan A 16edf3b140e0

Subscribe to this mod's changes

youtube-seo-thumbnail is a skill published in the GitHub repository deeployCO/youtube-seo-skills (9 stars, last pushed 5mo ago), licensed MIT. It adds 65 tokens to every session and 1,851 once invoked, about $0.0003 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.

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