thumbnail-design — Claude Code skill: YouTube thumbnail briefs

---
name: thumbnail-design
description: >-
  Design YouTube video thumbnails that earn the click — mobile-legible, one focal point, honest.
  Use when someone wants to design a YouTube thumbnail, improve CTR, brief a thumbnail, choose
  thumbnail text, or plan thumbnail A/B testing. Designs and briefs high-CTR thumbnails and writes
  the A/B test plan: a thumbnail is a promise, not a poster, designed as a unit with the title and
  legible on mobile. Uses the CLICK framework. Reads brand-profile + the video/title first. A HUMAN
  or an image/design tool (nano-banana/ideogram/Canva/designer) creates the final raster; the
  YouTube custom thumbnail is uploaded NATIVELY in Studio (WoopSocial has no thumbnail field) and
  Test & Compare is native; TikTok/IG-Reel covers use WoopSocial's cover field via those format
  skills. No clickbait, no unconsented real-person/deepfake faces, CTR never fabricated. Distinct
  from youtube-publishing-and-metadata (the metadata) and nano-banana/ideogram (which generate the
  raster this briefs).
version: 1.0.0
---

# thumbnail-design

A **design-craft skill** — write the promise, design the concept + text, produce the **brief**, and plan the
**A/B test**. The agent **designs + briefs + plans**; a **human or image tool makes the raster**; the
**YouTube thumbnail is uploaded + tested natively** (no WoopSocial field).

## The POV: a promise, not a poster — designed as a unit with the title
A thumbnail drives **~70–80% of click decisions**, and the viewer decides in **under a second** — so its job
is the **click that leads to a watch.** Two rules anchor everything: the **thumbnail + title are one unit**
(the thumbnail **shows**, the title **tells** — they never repeat), and it's a **promise, not a poster.**
That second rule is enforced by the platform: YouTube's native A/B test picks the winner by **watch-time
share, not raw CTR**, so a misleading high-click thumbnail **loses** to an honest one. Design for **mobile
first** — most viewing is on a phone, where simplicity and contrast win.

## Read these first
1. **brand-profile** — channel style/template (for consistency).
2. the **video and its title** (often from **youtube-publishing-and-metadata**/**youtube-long-form**/
   **youtube-shorts**).

## The framework: CLICK
(Depth: `references/the-click-framework.md`.)
- **C — Clarify the promise:** one-sentence promise; thumbnail + title as a unit (show vs tell, never
  repeat); promise not poster.
- **L — Lead with one focal point:** one/two hero elements, minimal background, parseable in <1s; one
  directional element.
- **I — Invoke genuine emotion:** expressive genuine face + gaze if it adds context (skip it otherwise);
  match the expression to the content.
- **C — Contrast + concise text:** complementary high contrast (avoid YouTube red/white, 60-30-10, B&W
  test, light+dark); 0–4 bold sans-serif words + outline, not a title duplicate; mobile-legible at ~168×94;
  safe zones; 1280×720, 16:9.
- **K — Keep testing:** 3 meaningfully-different concepts, one variable; native Test & Compare picks by
  watch-time share (not Shorts, needs traffic); a human uploads + runs it; keep a log; brand-consistent
  template.

## The reality (verify-quarterly)
Promise-not-poster + thumbnail+title-as-unit + watch-time A/B punishes clickbait; the three principles
(simplicity/contrast/emotion); faces (+20–30%, genuine, gaze, unknown-face-can-hurt); contrast/color
(complementary, avoid YT red/white, 60-30-10, B&W test); text (0–4 words, bold sans-serif, no title
duplicate); mobile-first + safe zones + specs (1280×720; 50MB cap since early 2026); brand consistency; native
Test & Compare (watch-time-share winner, also tests titles/combos, not Shorts, traffic-dependent):
`references/thumbnail-2026-reality.md`.
The promise template, design checklist, spec block, A/B plan + worked examples:
`references/design-and-test-recipes.md`.

## Honest scope (never violate)
- **The agent** writes the promise/concept/text/**brief** and can **critique a mockup** — but a **HUMAN or
  image tool** (`nano-banana`/`ideogram`/Canva/a designer) **creates the final raster.**
- **The YouTube custom thumbnail is uploaded NATIVELY in Studio — WoopSocial has no thumbnail field** — and
  **Test & Compare is native** (a human uploads + runs it). **TikTok/IG-Reel covers** are different: those
  use **WoopSocial's `cover` field** via `tiktok-video-publishing`/the IG skill.
- **No clickbait** (the thumbnail must keep the promise — the watch-time test punishes deception); **no
  unconsented real-person/deepfake faces**; **never fabricate a CTR** (real testing/native analytics only).
  (Scope, distinctions + connections: `references/scope-and-connections.md`.)

## Distinct from its siblings (route correctly)
**thumbnail-design (this)** = the thumbnail design craft + brief + A/B plan · **youtube-publishing-and-
metadata** = the title/description/tags metadata (points HERE for the thumbnail) · **nano-banana**/**ideogram** =
generate the raster this briefs · **tiktok-video-publishing** = the TikTok `cover` field · **hook-writer**/
**caption-writer** = text lines.

## Where this connects
Reads first: **brand-profile** + the **video/title** (**youtube-publishing-and-metadata**/**youtube-long-
form**/**youtube-shorts**). Pairs with: **nano-banana**/**ideogram** (render the brief), **hook-writer** (the
thumbnail words), **youtube-publishing-and-metadata** (title as a unit with the thumbnail),
**experimentation** (A/B discipline), **competitor-analysis** (preview against ranking thumbnails). Hands to:
a **human** to render + **upload the YouTube thumbnail natively** + run **Test & Compare**;
**analytics-and-reporting** reads CTR/watch-time back. The raster, native upload, and native A/B test stay
outside WoopSocial.

## Definition of done
A one-sentence promise written and the thumbnail designed as a unit with the title (show vs tell, no
repetition); one focal point with minimal background; a genuine face + gaze where it adds context (or none);
high contrast (complementary, not YouTube red/white, 60-30-10, passes the B&W test) legible in light and dark;
0–4 bold words with an outline that don't duplicate the title; mobile-legible at ~168×94 with safe zones and
1280×720 specs; an A/B plan of 3 meaningfully-different concepts changing one variable, scored natively by
watch-time share; the raster left to an image tool/designer and the YouTube upload + test left to native
Studio; no clickbait, no unconsented faces, no fabricated CTR; correctly distinguished from
youtube-publishing-and-metadata and nano-banana/ideogram.