How do I install the Thumbnail Ab Tester skill?

Run npx skillmds@latest add rahulcommercial/thumbnail-ab-tester in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Thumbnail Ab Tester safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Thumbnail Ab Tester?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Thumbnail Ab Tester free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Thumbnail Ab Tester?

rahulcommercial (@rahulcommercial) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Thumbnail Ab Tester by rahulcommercial

Name: Thumbnail Ab Tester
Author: rahulcommercial

Thumbnail Ab Tester

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.

File contents

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.

---name: thumbnail-ab-testerdescription: 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.---# Thumbnail A/B TesterGenerate 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 strategyFor 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 clarityVariant B — score 28/40 ...Winner: AWhy: 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.

Frequently asked questions