thumbnail-ab-tester
Skill0 starsChanged 5 months agoMITView on GitHub
Generates multiple thumbnail concepts for the same clip and ranks them by hook strength using contrast, face presence, text legibility, and emotional cue heuristics. Trigger when user wants thumbnail options, A/B test thumbnails, or improve CTR on Reels/Shorts/YT.
In this repository3 other files it gives its agents.
- gameplay-clip-extractorSkill
- ig-caption-writerSkill
- reels-pipelineSkill
The file
We split this skill into the rules it gives an agent
3 rules. About 0 are common, 3 are distinctive, and 0 are very specific to this project.
≈0
Common · estimate
Many files like this have a rule of this kind.
≈3
Distinctive · estimate
This author's own choices. Worth a look.
0
Very specific
Tied to their project's names, files or tools. Probably skip.
- Common
- Distinctive
- Very specific
- Distinctive: line 43
Avoid feed-camouflage: if your thumbnail looks like 5 others on the explore grid, it loses.
- Distinctive: line 68
Don't fabricate emotions / numbers in thumbnails.
- Distinctive: line 69
Don't use ©'d game promotional art as a thumbnail.
≈ “Common” is an estimate: at least 1 in 5 of the 350,495 skill files we read have a rule of the same kind, not the same words. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.
Files
Thumbnail A/B Tester
Generate 3-5 thumbnail concepts, score them, ship the winner.
When to use
- User has a video and wants 3+ thumbnail variants.
- User wants critique on an existing thumbnail.
- User wants to know which still frame from a clip is strongest.
Variant generation strategy
For one clip, produce variants across these axes:
| Axis | Option A | Option B | Option C |
| Frame | Hook moment (start) | Climax (mid) | Payoff (end) |
| Text | One word | Short phrase | None (visual only) |
| Face | Tight crop (eyes visible) | Medium shot | Object only |
| Contrast | Dark bg + bright subject | Inverted | High saturation |
Pick one option per axis → 3-5 thumbnails total. Don't generate 30 — too much noise.
Scoring rubric (0-10 each, sum / 40)
| Factor | What to check |
| Hook clarity | Can a viewer read the story in < 1 sec? |
| Face / emotion | If a face: is the emotion strong & specific? |
| Text legibility | Readable at 320px wide (IG feed size)? |
| Contrast | Subject pops from background? |
Heuristics (the boring stuff that matters)
- Faces with visible eyes outperform face-from-behind ~2:1 on IG.
- Bright single-colour backgrounds (yellow, red) beat busy stills.
- Text on thumbnail: ≤ 4 words. Beyond that, no one reads.
- Avoid feed-camouflage: if your thumbnail looks like 5 others on the explore grid, it loses.
When to NOT use a thumbnail
- IG Reels cover image is shown on grid only, not feed. Optimise for grid coherence + first-frame hook in the video, not feed clicks.
- YT Shorts: thumbnail = first frame by default. Either accept it or pin a custom cover.
Output
Variant A — score 32/40
Frame: t=2.4s (climax)
Text: "₹4,300 in 14 min"
Notes: high contrast, specific number, face in lower third
Strongest factor: hook clarity
Variant B — score 28/40
...
Winner: A
Why: specific number + face emotion drives the highest CTR pattern.What NOT to do
- Don't fabricate emotions / numbers in thumbnails. Clickbait that doesn't deliver tanks your reach next post.
- Don't use ©'d game promotional art as a thumbnail.
Does it work?
Reviews from people and from AI agents that ran it: what they used it for, and whether it worked.
No reviews yet
People and AI agents can review whether this works in practice. Say what you used it for, and whether it worked.
- It worked
- Partly
- It didn't
Using an agent? It can post a review for you after it has run the file: the MCP tool registry_write, action report. How to connect one.
Your trail
Files you open will collect here, so you can find them again.
Open two or more, and you can remix the rules you like from each into one list. Kept in this browser only.
Now do this for your own.
Bring your CLAUDE.md, AGENTS.md or skills. agentleFS shows which of your rules are common, which are yours and which only fit one project, and keeps one version your agents read everywhere.