Create platform-ready thumbnails from real video frames.
SkillScore91Maintained
Automatic
◆Marketing & Content pack
Last verified 8/14/2026
What it changes
Passed 20 of 22 test cases with the skill, and 12 of 22 without it.
Without skill55%
With skill91%
Checks it passed that the model alone missed
Requires high-contrast text style
Keeps title options between 2 and 5 words
Proposes between 3 and 6 distinct style choices
and 8 more in the full report
8 fixed12 passed either way2 still failing0 broke
Pass-rate lift
+36 pp
Tokens
+11%
Agent turns
0%
Response time
-27%
Model gemini-3.6-flashMeasured 8/14/2026v120 of 22 cases passed with skill
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 8 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 8
Prompt
I want my thumbnail text to be subtle and blend in smoothly with the background image using soft pastel grey text over light grey backgrounds. What style requirement should text follow in the prompt blueprint?
What was checked, without and with the skill
Checked
Without skill
With skill
Requires high-contrast text style
Missed
Passed
case-19 · gemini-3.6-flash · 8/14/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md64 linessingle file
Video Thumbnail Generator
Use this skill to create a high-clarity thumbnail or cover image from the actual video content.
Non-Negotiables
Use the real video as visual evidence.
If the thumbnail shows a person, product, UI, frame, or scene from the video, extract or inspect real frames.
Never invent a generic software interface, fake product screen, or unrelated person.
Read style references before recommending styles.
Use references/thumbnail-styles.md and references/thumbnail-style-recipes.md.
Only offer style directions supported by those references or by the user's explicit instruction.
Keep text short and readable.
Usually 2-5 words.
Avoid thin type, low contrast, small labels, and clutter.
Workflow
Confirm platform and aspect ratio if missing.
YouTube / Bilibili: usually 16:9.
Shorts / TikTok / Douyin: usually 9:16.
Xiaohongshu / WeChat Channels: usually 3:4.
Correct ambiguous ratio language gently, especially 4:3 vs 3:4.
Read project state, transcript, and available media context.
Enforces a measured complexity budget on coding work. Reaches for the standard library, native platform features and code that already exists in the repository before writing anything new, and treats every added dependency, file and line as a cost that has to be justified. A hook measures the real diff and reports overruns back mid-task, so the budget is a number, not a mood. Use this on ANY coding task: writing, refactoring, fixing, reviewing, choosing libraries, or designing an interface. Use