a18: concept-seed mechanism — derive grounded shortlist, script assigns build index + challengers; contract adopts UNIQUE/NOT-TEMPLATE/OWN-WORLD/STORY/FIRST-VIEWPORT

Contract-probe campaign findings (evals repo, notes/fable-oneshot-craft-plan.md):
a single model's resonance ranking is deterministic (30/35 identical
concepts across 16 framings); dice must come from the script, mirroring
the palette-seed result. Derived candidates stay grounded in the
audience's world + subject's cultural home; challengers win only on
identification x clarity; incumbent-with-deliberate-idea overrides the
roll. Validated at contract level on 01-observability + r10-lektor
(teletext ranks #3 for lektor; assigned index 3 produced it).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

skill/reference/new-work.md

@@ -12,9 +12,9 @@ Name one concrete subject, its audience, and the page's single job. The subject'
 
 ## Decide, then build
 
-Sketch three directions in one line each before choosing: they must differ in concept, not in polish. If the direction you'd instinctively ship is the one any competent studio would also reach for, it is the default wearing your name; pick the direction that is most specific to this subject and still serves the mode. <!-- rule:skill-three-directions -->
+Derive the concept with this procedure, recording each step in your reasoning before the next begins. One: state the product's unique mechanism in one sentence, the thing competitors cannot truthfully claim. Two: competitive analysis; describe the page this category always ships, and the counter-position page a contrarian ships, and treat both structures as off the table. Three: from the audience's world and the subject's cultural home, list five concrete materials, objects, documents, or rituals they know by heart, each with one line on why it resonates and can carry the mechanism, ordered by resonance. Four: run `node {{scripts_path}}/concept-seed.mjs` and follow what it prints: it assigns which candidate to build (your top-ranked candidate is what every run would ship; a single ranking is deterministic, so the dice come from outside) and supplies challenger forms to weigh against your list on exactly two axes, audience identification and product clarity. Five: the chosen form supplies the page's structure, reading order, and component conventions; the product supplies every fact. Conversion conventions are furniture inside the form, not the form: a hero that hooks in one line, a visible primary action, a legible reading order. The costume check closes the step: if a visitor would notice the form before the product, the candidate fails; take the runner-up. <!-- rule:skill-concept-procedure -->
 
-Then state the chosen direction as a contract, written as a comment block at the top of the artifact (invisible to visitors, binding for you): the concept in one line; what a visitor would describe an hour after one viewport; why this page could not be the modal competitor page; the signature; and what the first viewport does instead of a generic header. If any answer is missing or reads like a mood, the direction isn't decided yet. The build is judged against this contract; delivering different pixels than the contract promises is a defect on whichever side is weaker. When a user can respond and the work is substantial, pause there for confirmation; when the harness has native image generation, follow [codex.md](codex.md)'s mock flow before code. When no user can respond, record the decision in your reasoning and proceed without pausing. Either way the decision comes first; code that precedes a direction is the template reflex in motion. <!-- rule:skill-decide-then-build -->
+Then state the chosen direction as a contract, written as a comment block at the top of the artifact (invisible to visitors, binding for you), five short blocks, two hundred words at most. UNIQUE: the one idea this page owns. NOT-TEMPLATE: how the page's structure differs from the category's standard arrangement, stated plainly and honestly. OWN-WORLD: the palette and component language, specific enough that the components and colors alone, shown without content, would be recognizable as this page's world and nobody else's. STORY: what the visitor understands, believes, and does, from first viewport to action. FIRST VIEWPORT: the exact composition, what is where and at what scale. If any block is missing or reads like a mood, the direction isn't decided yet. The build is judged against this contract; delivering different pixels than the contract promises is a defect on whichever side is weaker. When a user can respond and the work is substantial, pause there for confirmation; when the harness has native image generation, follow [codex.md](codex.md)'s mock flow before code. When no user can respond, record the decision in your reasoning and proceed without pausing. Either way the decision comes first; code that precedes a direction is the template reflex in motion. <!-- rule:skill-decide-then-build -->
 
 ## Plan, self-check, build