youtube-thumbnail

youtube-thumbnail is a skill for Claude Code from alebgl77/claude-inc. It costs 120 tokens per session (1,033 once invoked), scanned A, original, MIT.

A YouTube thumbnail planning and testing workflow. It creates several thumbnail concepts and checks whether they remain understandable and readable on small screens.

In plain words
What is it for?
It develops thumbnail concepts with a focal subject, short overlay text, and contrasting colours, then scores curiosity and mobile readability for choosing an initial design and later variations.
Why use it?
It helps identify weak video packaging when viewers are not clicking, while checking that the thumbnail and title create interest without repeating each other.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the claude-inc plugin — 50 skills, 3 commands, 8 agents shipped together

Good fit It develops thumbnail concepts with a focal subject, short overlay text, and contrasting colours, then scores curiosity and mobile readability for choosing an initial design and later variations.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/alebgl77/claude-inc/youtube-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 alebgl77/claude-inc --skill youtube-thumbnail
Clone the repo
git clone --depth 1 https://github.com/alebgl77/claude-inc

Made for: Claude Code.

Or install claude-inc, the plugin that ships this one along with the rest of its 50 skills, 3 commands, 8 agents.

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-thumbnail

README.md
[![agentmods](https://agentmods.dev/badge/skills/alebgl77/claude-inc/youtube-thumbnail.svg)](https://agentmods.dev/skills/alebgl77/claude-inc/youtube-thumbnail)
Your own site
<a href="https://agentmods.dev/skills/alebgl77/claude-inc/youtube-thumbnail"><img src="https://agentmods.dev/badge/skills/alebgl77/claude-inc/youtube-thumbnail.svg" alt="Measured on agentmods" height="20"></a>
Per session 120 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,033 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00120 $0.01033
Opus 5 $0.00060 $0.00517
Sonnet 5 $0.00024 $0.00207
Haiku 4.5 $0.00012 $0.00103

Measured 4d ago against content hash 5d802bc426c9, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

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 4d 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.

skills/youtube-thumbnail/SKILL.md · 86 lines

How it starts

The opening of the file, as written. The whole thing — 86 lines — stays where its author put it; the contents beside it link to each section on GitHub.

YouTube Thumbnail — Cover Tester

"Test thumbnail covers"

When to use

  • "Thumbnail ideas for my video about ."
  • "Which of these two covers should I use?" — a scored verdict, not a shrug.
  • CTR is flat and packaging is the suspect: "my CTR is stuck at 3%."
  • Pre-production: designing title + thumbnail as one package before filming.

Workflow

  1. Get the inputs: video topic, the exact title, the target viewer, and where the impressions come from (browse, suggested, search) — thumbnails compete differently on each surface.
  2. Define the ONE emotion or question the thumbnail must trigger. The thumbnail asks a question the title answers (or the reverse) — the two must never repeat each other.
  3. Draft 3–5 concept briefs. Each specifies composition (focal point on a rule-of-thirds intersection), face or object (expression, prop, angle), a text overlay of three words or fewer (or none), and a palette with deliberate contrast against YouTube's white/dark UI and red accents.
  4. Curiosity-check each concept: does it open a loop the title closes? Does it spoil the payoff? Does it still make sense with the title covered?
  5. Run the mobile legibility test: judge each concept at 168×94 px — focal point readable, overlay text at 25%+ of frame height, nothing critical under the timestamp corner or lost at the edges.
  6. Score every concept /10 with the rubric: clarity at a glance (3), curiosity (3), contrast vs UI (2), title synergy (2). Rank them.
  7. If an image generation tool is available in the session, produce mockups of the top two concepts; otherwise ship briefs precise enough for a designer or a Canva session.
  8. Write the A/B rotation plan: which concept launches, the numeric swap trigger (e.g. CTR under 4% after 48 hours or 10k impressions), and what the variant changes — exactly one variable.

Output format

## Thumbnails: "<video title>"
Target emotion/question: <one line> | Surface: browse / suggested / search

### Concept 1 — <name>
- Composition: <focal point + layout>
- Face/object: <expression or prop>
- Overlay: "<3 words max>" | none
- Colours: <palette + contrast note vs YouTube UI>
- Curiosity check: pass / fail — <reason>
- Mobile check (168×94): pass / fail — <reason>
- Score: <n>/10 (clarity /3, curiosity /3, contrast /2, synergy /2)

### Concept 2–5 — <same structure>

### Verdict
Launch: Concept <n> — <one-line reason>
A/B plan: swap to Concept <m> if <numeric trigger>; variable changed: <one thing>
Mockups: <file paths | "no image tool available — briefs are designer-ready">

Read the full file on GitHub · 86 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. 4d ago First seen · 86 lines · 120 tokens per session scan A 5d802bc426c9

Subscribe to this mod's changes

youtube-thumbnail is a skill published in the GitHub repository alebgl77/claude-inc (14 stars, last pushed 5d ago), licensed MIT. It adds 120 tokens to every session and 1,033 once invoked, about $0.0006 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 2026-09-04.

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