opondo300/born-builders-agent-library/hook-engine

Hook Engine

What this skill adds — copywriting-craft covers appeal hierarchy, awareness levels, specificity, and structure. attention-belief covers the neuroscience of attention gates, information gap theory, and Zeigarnik. This skill does not repeat those. It covers what they don't: the production system for generating hooks, the format-switching framework, and the derived rules that cross all of them.

When to Invoke

Before writing any hook — headline, email subject, video first line, carousel cover, static ad copy, or cold email opener.

The Derived Ruleset

Eight rules derived from first principles. They override intuition every time intuition and the rules conflict.

Rule 1: A hook is not a clever line — it is a prediction violation. The brain's cortex fires (P300) when the next thing violates what it modelled was coming. "Clever" produces admiration. Prediction violation produces compulsive attention. These are different. The test: does this sentence say what the audience expects a sentence in this context to say? If yes, it is not a hook.

Rule 2: Complete information kills the hook. Incomplete information kills the conversion. The Loewenstein information gap functions as a dopaminergic drive state — but only when partial information is present. A vague question produces no gap. A complete answer produces no curiosity. Maximum drive state sits at approximately 50% revelation. Error mode A (too vague): "Here's the mistake most people make." Error mode B (too complete): leading with the answer, then explaining. Thread the middle: name the territory, withhold the map.

Rule 3: A strong hook with weak body is the worst algorithmic outcome — not a neutral one. This is the most commonly violated assumption. TikTok's data (Kaggle Viral Shorts: hook strength 0.95, completion rate 22%) confirms that baiting attention without delivering on it is penalised harder than never baiting it at all. The hook is a contract with the algorithm and the reader simultaneously. Write the body first. Hook second.

Rule 4: Identity beats information. Always. Information hooks have a half-life. Identity hooks do not. "Do You Make These Mistakes in English?" (Sackheim, 1919) ran for 40 years. Nike "Just Do It" is now 37 years old. The mechanism: identity is not consumed. Information is consumed and depreciates. When the audience's identity can be activated — who they see themselves as, who they're trying to become, who they don't want to be — that hook outlasts any statistic or fact. Check: does this hook sell them information about the world, or does it sell them a version of themselves?

Rule 5: Customer language beats copywriter language. Every time. Wiebe's "I smell like a CEO now" (from a 3-star Harley-Davidson review) doubled CTR and halved CPC. The mechanism: the reader's brain recognises its own language before it recognises new language. Mine the 3-star review (specific frustration without total abandonment) — not the 5-star (enthusiasm without tension) and not the 1-star (anger without actionability). The 3-star contains the exact cognitive frame of a prospect who is aware of the problem and hasn't yet decided. That language is the hook.

Rule 6: The first 5 variants are always the obvious ones. They are worth writing and worth discarding. Halbert wrote on physical cards, shuffled them, discarded. Upworthy ran 25 minimum per piece from 32,487 experiments. The implication is not "write more." It is: the first 5 variants are where the obvious ideas drain. Variant 6 onward is where differentiation begins. Do not ship a hook from the first 5. Write 15. Kill the first 5. Choose from the remainder.

Rule 7: Video has two hooks. They are not the same hook. Content hook: what the viewer will get. Story hook: what is at stake. A video with only a content hook loses viewers at 30 seconds when curiosity is satisfied. A video with only a story hook loses viewers who don't yet care about the character. Both must be present in the first 30 seconds. Thumbnail + title carry the content hook before play. First 30 seconds carries the story hook.

Rule 8: The format sets the pre-attentive constraint, not the creative constraint. Static: color and contrast fire at 50ms (Lindgaard 2006) — the gist is set before a single word is read. The visual IS the hook. Words confirm it, they do not make it. Carousel: the cover slide hook is compressed because two impressions are available per post (Mosseri's re-show mechanic — non-swipers get served from slide 2). Video: the TikTok decision window is 0.3–0.8 seconds, not 1.7 seconds (the 1.7s figure is Meta's; TikTok's own data is faster). Email subject: 2–4 words at 46% open rate (Belkins, 5.5M B2B emails); personalization increases opens 31% and replies 133%. Written copy: the headline is 80% of the ad (Ogilvy); the opener's single job is pulling the eye to line 2, not explaining anything.

The Production Workflow

Step 1 — VOC Mine before writing. Pull 15–20 reviews, forum posts, or customer quotes in the exact category. Find the 3-star entries. Extract the phrase that is most specific to the frustration. That phrase is the raw material. Don't paraphrase it — use it.

Step 2 — Identify the awareness level (from copywriting-craft: Schwartz's 5 levels). Most aware → Short, direct, offer-first. Problem aware → Lead with the exact problem named in their language. Unaware → Story-first, never feature-first.

Step 3 — Write the body. Then write the hook. The hook is a promise the body must keep. Writing the hook first produces a mismatch 70% of the time and algorithmic penalty when deployed. Write the core argument or content first. The hook emerges from knowing what it needs to promise.

Step 4 — Write 15 variants. Discard the first 5. Variant formats to cycle through: number (specificity), loss frame (2.25x weight vs. gain — Kahneman/Tversky), identity activation, prediction violation, VOC verbatim, contrarian position, and implied transformation. One variant per frame. None should share a mechanism.

Step 5 — Apply the format constraint. Run the format check from the framework below. The hook that survived Step 4 may need recompression for the format's pre-attentive window.

Step 6 — Evaluate against Rule 3. Does the body deliver what the hook implies? If not, rewrite the body or rewrite the hook. Do not ship the mismatch.

Format-Switching Framework

The Diagnostic

Before any hook ships, answer these in order. A "no" stops the process:

1. Does this violate a prediction the reader would have made in this context?
2. Does it reveal enough to open a gap without closing it?
3. Is the body strong enough to justify this hook?
4. Is this variant from the second half of the 15-variant set?
5. Does the language come from the customer or from the copywriter?
6. Does the format constraint match the pre-attentive window of the platform?