What you get
Instant Score* uploads 2–4 thumbnails, runs Diagnose on each, and names a feed-size winner. Same pixels, same scores — not a CTR prediction.
Live AI Test is the other tab: it rotates real thumbnails and titles on your channel and measures view-count change.
Feed size matters
Most clicks are decided at mobile feed size (~168×94). Always review the small preview before you publish.
Limits
Free usage may be rate-limited. Logged-in plans raise or remove caps depending on your tier.