Thumbnail Concept
A video topic → several high-CTR thumbnail concepts with image-gen prompts.
Purpose
The thumbnail decides whether good content gets watched. This skill produces a few distinct, honest, high-contrast thumbnail concepts — each with a layout, a short text overlay, a color logic, and a ready image-generation prompt — so the creator can pick and generate quickly.
When it fires
- Keyword triggers:
thumbnail,cover art,thumbnail ideas,ctr,video cover - File triggers:
thumbnails/** - Command triggers:
/thumbnail-concept
Inputs
| Input | Required | Notes |
|---|---|---|
topic | yes | Video subject + the promise. |
subject | no | Hero image/asset (e.g. a nebula, a rocket). |
count | no | Number of concepts, default 3. |
Workflow
- Find the visual hook — the single image idea that conveys the promise. ✅ Check: readable at small size.
- Per concept: layout (subject placement, rule-of-thirds), overlay text (≤4 words, high contrast), color/contrast logic, and emotional read.
- Honesty check — the thumbnail must match the actual content (no bait).
- Image-gen prompt — a concrete prompt to produce the background/subject; if using NASA imagery, note the rights step.
Output contract
{
"concepts": [{
"layout": "string",
"overlay_text": "string — ≤4 words",
"color_logic": "string",
"emotional_read": "string",
"image_prompt": "string"
}]
}
Tools & MCP
- Tools:
Read. MCP: optional image-gen MCP.
Quality bar
- Overlay text ≤4 words and legible at thumbnail size.
- Concept matches the real content (no clickbait).
- High contrast / clear focal point.
- Rights noted if real agency imagery is used.
Example
Input: "Why Webb sees what Hubble can't" → 3 concepts, each with a 2–3 word overlay, contrast logic, and an image prompt.
Built on SIP — Starlight Intelligence Protocol Substrate: starlightintelligence.org/protocol v1.1.0 Layers used: [file-contract, attestation, sovereignty] Vertical: starlight-agent-skills · portable capability layer