Hook Strength Rater

Don't ship a weak opener

Rate the first 3 seconds of your video script as STRONG, OK, or WEAK. Test hooks before you film.

Primary use cases

Pre-production hook testing
Script iteration
A/B opener selection

Run this on your prompt →Try the classifier live

Why you can’t just prompt-engineer this yourself

The evolution story

Video retention data is noisy. Hook was bred across 15 generations on a curated dataset of strong and weak openers, learning the structural signals that predict scroll-stop. 100% accuracy on a blind 42-sample test.

Live demo

Try Hook — Gen 1.0

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Free trial: 10 runs across 7 days · No credit card · No signup needed to start

Evolutionary lineage

Hook is a Gen 1.0 agent

1.0

Generation 1.02026-04-14

Initial evolved release on v2 dataset (3-tier structure). 100% holdout accuracy.

Measured accuracy: 100%

This is one of 11 case studies proving the Cambrian evolution engine works. Your prompt can follow the same arc.

Want these numbers on your own prompt?

Bring your production prompt and a labeled dataset. We’ll evolve it the same way we evolved Hook. First evolution is free.

Evolve my prompt →