Scroll Craft

scroll-craft

Scroll is the only input every visitor already knows how to use. This skill treats it as a timeline: the wheel is a scrubber, the page is a film with real text on top, and each section behaves differently enough that the visitor keeps going to find out what the next one does.

What you produce: an interview brief, a page grammar, a customer-journey map, a feeling curve with one engineered peak, a scroll score, one signature move, generated assets, one real HTML page on a token-driven design floor, and a strip of screenshots proving it holds up at every scroll position.

What this is not

It is not "generate a flythrough and drop text on it." That approach produces one device applied to a whole page, and every site built that way is recognisable at a glance: same claymation diorama, same centred copy, same 01 / 06 counter, same "scroll to explore" nudge. Five sections that behave identically are one section shown five times.

Four rules follow from that, and they are the spine of this skill:

1. Variety is the product. A page uses at least four device families and never the same device twice in a row. Read references/devices.md.
2. The world is photographic unless the brand is genuinely illustrated. Soft matte low-poly clay diorama is banned as a default. Read references/worlds.md.
3. No continuous chain. A single unbroken camera flight is the most expensive and most fragile thing you can build, and it exists only to hide cuts between scenes. Vary the device instead and the cut disappears for free, because the visitor is not watching one film. Chain only when the brief is literally "one continuous journey."
4. A different world is not a different page. The device kit varies how a page looks. Structure is a separate axis, and it has to be decided deliberately or every build inherits the same skeleton. The first four builds did exactly that. Read references/uniqueness.md.

Nate's standing hero preference

Dimensional layering is a baseline requirement for a premium marketing hero. Plan independently moving background, subject, foreground, and atmospheric planes before requesting assets. A beautiful single background with text fades does not satisfy this preference. Depth must come from visible separation, occlusion, and controlled differences in movement, while the headline stays readable and the scene tells one clear story.

Read references/hero-depth.md before planning the hero or generating its assets. It covers clean plates, genuine alpha cutouts, shared contact anchors, typography between planes, restrained scroll choreography, mobile art direction, and visual acceptance, with the approved Sonder example. Use the composition that fits the chosen grammar; do not repeat Sonder's scene or impose pinning on a grammar that forbids it. Honor explicit static or simpler directions, and keep depth in the static composition when motion is reduced.

Approved collection standard

Read references/approved-collection.md before planning a premium marketing site. It distills the ten-site rebuild Nate approved: real brand research, layer contracts, meaningful pointer/scroll depth, appropriate photographic or 3D rendering, distinct navigation and endings, useful interactions, mobile art direction, and evidence from the final package. These are execution principles and worked examples, not a reusable page skeleton.

Step 0: The brief and creative authority

Establish the brief before generating anything. Reuse answers and assets already provided. When the user explicitly delegates creative direction (for example, "use your judgment" or "I want to get out of your way"), write a Self-authored under explicit creative delegation brief and proceed. Cover the eight topics below, distinguish evidence from assumptions, and do not invent user quotations or force another interview/approval checkpoint.

Otherwise, interview for the missing decisions. Ask actual questions, record the answers, and avoid inferring an entire brand from its name.

The skill is a range instrument, not a house style. The human brings intent and whatever assets they own; the interview is where that turns into the right kind of page: one unbroken world, distinct scenes, printed chapters, a live surface. The skill can do any of them. The interview decides which.

Keep it short. Eight questions, asked in one pass:

1. Vibe in three to five words, plus up to three references from any medium. A film, an album cover, a shop, a magazine, a game. Not "sites you like": naming sites is how a page ends up looking like an existing site.
2. The scroll journey, section by section, in their words. What the visitor should hit first, what comes next, what the last thing is. Their sequence, not a menu you offered.
3. The energy curve. Where it should feel calm, where it should feel intense. A page that is loud the whole way is as flat as one that is quiet the whole way.
4. How should someone feel while scrolling, stage by stage, and what is the ONE moment they should remember? Energy is loudness. This is emotion, and the two do not line up: on a loud page the quiet act can be the most intense. The stage-by-stage answer becomes the feeling curve, the one moment becomes the peak. Both are required in BRIEF.md. See references/feel.md.
5. One thing this site should do that no site they have seen does. This is the seed of the signature move. Push for a real answer; "be memorable" is not one.
6. How far from premium-minimal they want to go. Offer the range in uniqueness.md §5: brutalist, maximalist, playful, retro, dense, editorial, premium-minimal. Their answer governs the aesthetic family, not your taste.
7. One unbroken world, or distinct scenes? Should the whole page feel like one continuous place the scroll flies through (worldflight, see references/worldflight.md), or like separate scenes, chapters, or cuts? This is the single biggest structural fork, and it is their call, not a device you pick later. Offer both plainly; neither is the default.
8. What assets do they already have? Footage, photos, product shots, a brand kit, clips of themselves. Real assets anchor the world and cut generation cost; the answer decides what gets graded and encoded versus generated. "Nothing" is a fine answer and means a fully generated world.

Write the answers into <workspace>/builds/<name>/BRIEF.md before any act planning, in their words, not paraphrased into marketing prose. Everything downstream reads from that file.

BRIEF.md must contain, at minimum:

• The eight topics, with verbatim user answers where supplied and clearly labeled authored decisions where delegated.
• The feeling curve. One line per act: the emotion, then what on screen causes it. Written before the acts exist, added to as the score fills in.
• The peak. The one moment, written as the sentence a visitor would say to a friend, plus which act it lives in.
• The completed tell-someone sentence. "It's the site where ___", filled with an experience, not a device name.
• Any authored silence, so the verification pass can tell it from dead scroll.

references/feel.md is the spec for all four.

If the human is genuinely unreachable and the run is fully autonomous, write BRIEF.md yourself: answer all eight questions in the brand's voice, mark the file Self-authored, not interviewed at the top, and say so in the final report. A self-authored brief without delegation is a fallback. Explicit delegation above is a normal supported workflow and does not require the human to be unreachable.

Bootstrap

Environment, not a stage of the work. Do it once the interview is answered and before Step 1.

Run the preflight rather than checking by hand. It knows the failure modes that otherwise surface later as misleading errors, chiefly a stripped ffmpeg that reports a missing filter as a syntax error in your command:

node <skill>/scripts/doctor.mjs

It reports node, a full ffmpeg build, playwright and Chrome, the API key, and the resolved workspace. Required failures exit non-zero. Say plainly which items are missing rather than working around them silently.

The workspace

Builds and the fingerprint registry live in one directory, and it is resolved, never assumed:

node <skill>/scripts/workspace.mjs --ensure     # prints it, creates it, seeds the registry

Resolution order, first hit wins:

1. SCROLLCRAFT_HOME
2. the nearest .scrollcraft.json walking up from the cwd, { "workspace": "..." }
3. <project root>/scrollcraft, where the project root is the nearest ancestor holding a .git

So a build folder is <workspace>/builds/<name>/ and the registry is <workspace>/FINGERPRINTS.md. The registry starts empty: the gate exists to stop you repeating yourself, so your first build has nothing to clear.

If you already keep builds somewhere else, drop a .scrollcraft.json at your project root pointing at it and nothing moves.

The rest

1. KIE_AI_API_KEY, only if you are generating assets. A build from the user's own photos and footage needs no key and no spend, and that is a first-class route, not a fallback. Confirm balance with node <skill>/scripts/kie.mjs probe. A still costs cents and a 5s clip costs more; a six-act page with two clips is a small spend, not a large one.
2. A brand kit if one exists (colours, logo, type, existing product shots). If the brand has a folder in this repo, read it before generating anything, and obey its hard rules. A brand that forbids invented numbers means no stat counters, however good they look.

Copy engine/scrollcraft.js and engine/scrollcraft.css into the build folder. Never edit the engine per-project; it is the mechanism. Theme it with tokens and write your own markup.

Step 1: The brief, journey first

The subject is the user's to state. Ask it open, in plain prose, never as a fabricated multiple-choice list of industries: a made-up menu biases them and reads as you deciding their business for them.

Step 0 already covered vibe, sequence, energy and range. Do not ask any of it again. Ask only what you cannot sensibly default:

1. What is this, and who is it for? One or two sentences in their words.
2. What must the visitor believe by the end? The single sentence the page exists to install. Not a feature list. If they give three, make them pick.
3. What does the visitor do next? One action. One label for it, used everywhere on the page.
4. What do you already have? Logo, palette, photography, product shots, footage, a brand doc. Real assets beat generated ones every time.
5. Art direction: offer the worlds in references/worlds.md as a real choice, and say they can go their own way.

Then write the journey before anything else: four to seven beats, each one a shift in what the visitor knows or feels.

1  Recognition   they see their own morning
2  Tension       the cost of it, named plainly
3  Turn          the thing that changes
4  Substance     why it holds up
5  Range         what they can choose
6  Commitment    the one action

Beats are the spine. Sections serve beats; a section that serves no beat is cut, however nice the shot is. Resolve the journey before generating assets. Show it to the user when their decisions are needed; under explicit creative delegation, record the chosen journey and proceed within the authorized scope.

Step 2: Grammar, gate, then score

Three things in order, and the first two come before any act planning. Full detail in references/uniqueness.md.

Pick a grammar. Start with the eight defined grammars and their constraints. A new grammar is allowed when its navigation, sequence, ending, and explicit bans describe a different structure; a new label alone earns no credit. Filmic one-shot is the one the first four builds all used, so choosing it again means saying in the report why the other seven did not fit the interview. Nav, hero and close all follow from the grammar; they are not decided separately.

Invent the signature move. One bespoke interaction that lives on this site alone, coded in the page, not a parameter change to a kit device. Question 5 of the interview is the seed. The engine stays untouched.

Run the fingerprint gate. Read your registry at <workspace>/FINGERPRINTS.md (see The workspace in Bootstrap; run node <skill>/scripts/workspace.mjs to print the path). The planned build must differ from every existing row on at least 4 of 6 dimensions: grammar, nav treatment, hero device, act-sequence shape, close pattern, signature move. Four against each row individually. If it fails, change the plan, not the log.

Write the feeling curve before the score table. One line per act: the emotion, then what causes it. Curve first, acts second, because a device chosen before the feeling is a device looking for a reason. Two adjacent acts with the same feeling means one is filler, and it is cheaper to cut it here than after the assets exist. Name the peak in the same pass and give it the largest span on the page. Full method in references/feel.md.

Then assign each beat a device. Do it deliberately and write it down as a table:

That table is a filmic score. It is the right shape for one grammar and the wrong shape for the other seven, so read your grammar's leans-on and bans list before filling in a row.

Checks before you build:

• The grammar's bans hold. A grammar that forbids pin forbids it here too, however well it would have worked.
• Four or more distinct device families. Fewer means the page has one idea.
• No device family twice in a row.
• At most two scrub acts. Video is the heaviest thing on the page, and the third one stops being a surprise.
• No two adjacent acts carry the same feeling. If they do, one is filler.
• One act is the peak and it has the largest span by a visible margin. The act before it is quieter than it is.
• Every act earns its scroll span. Eight to fourteen viewport-heights is a pacing reference for longer cinematic pages, not a quota. Shorter editorial, gallery, or working-surface grammars should stay short when the journey is complete. Never add filler or empty pinning to hit a length target.
• The act count and total length do not land in the 6-to-7 acts at 13.6-13.8vh band that all four prior builds hit. That band is a fingerprint dimension now.

Step 3: Generate the assets

Full pipeline, prompt scaffolds and model notes: references/assets.md.

Short version:

node <skill>/scripts/kie.mjs still "<style preamble>\n\n<scene>" out/01-hero.png --ar 16:9 [--ref brand-can.png]
node <skill>/scripts/kie.mjs shot  "<camera move>" out/01-hero.png out/01.mp4 --dur 5
bash  <skill>/scripts/encode.sh out/01.mp4 assets/01.mp4
bash  <skill>/scripts/encode.sh out/01.mp4 assets/01-m.mp4 mobile

Four things that decide whether this looks premium or generated:

• One style preamble, reused verbatim in every prompt. This is what makes six separate images look like one shoot. Write it once, never paraphrase it.
• Look at every asset before you use it. Read the PNG. Generation is cheap and rerolling is cheaper than shipping a bad frame.
• Encode for scrubbing, not playback. encode.sh sets a dense GOP because seeking walks from the previous keyframe. A normal web encode plays perfectly and scrubs like mud.
• Layer the hero. Cut the scene into planes that scroll at slightly different rates, with the product parked between the mid and foreground planes. Depth from differential movement is the cheapest premium signal on the page. The recipe and its traps are under parallax in references/devices.md.

Step 4: Build the page

Write real HTML. Real <h1>, real <p>, real links, real reading order. The engine reads data-sc-* attributes off your markup and drives it; it never generates DOM. A runtime that builds the page from a config object is exactly why every site built on one looks the same.

Start from references/template.html. The device patterns are in references/devices.md; the spacing, type, depth and colour rules are in references/taste.md. Read taste.md before writing markup, not after, and build without announcing the checklist.

Theme by overriding tokens, six values and two fonts:

:root {
  --sc-canvas: #0A0806;  --sc-surface: #16110E;
  --sc-ink:    #F5EBDD;  --sc-ink-soft: #A2968A;
  --sc-accent: #FF5A3D;  --sc-accent-ink: #15110F;
  --sc-font-display: "Archivo", system-ui, sans-serif;
  --sc-font-text:    "Geist", system-ui, sans-serif;
}

Step 5: Verify by scrolling it

Apply the final-source and deployment checks in approved-collection.md §7. Use safe headless automation with native pointer lock/capture disabled in every context. Inspect actual pixels, phone compositions, and intermediate states; test useful controls, downloads, and form outcomes in the final package.

Not optional, and not "it should work." A scroll page has no single state: every position is a different frame, and the failures live between the two you happened to look at. Full procedure: references/verify.md.

cd <build project> && npm i playwright-core     # once
node <skill>/scripts/serve.mjs --root . --port 4500 &
node <skill>/scripts/shoot.mjs --url http://localhost:4500 --out lab/shots
node <skill>/scripts/shoot.mjs --url http://localhost:4500 --out lab/mobile --width 390 --height 844
node <skill>/scripts/shoot.mjs --url http://localhost:4500 --out lab/reduced --reduced-motion

The harness walks each act at six positions, waits for the scrub video to actually settle, and reports dead scroll, cues that never reach full opacity, and contrast measured on the composited page at the brightest frame under each line. It writes a contact sheet.

Then do the part the harness cannot: read sheet.png. It proves a clip advances; it cannot tell you the composition is good, the motion is smooth, or the page means anything. Also tab through for focus order.

Then run the feel check (references/feel.md §6). Scroll the page cold, write one word per act for what you felt, and only then open BRIEF.md and diff it against the intended curve. Where they disagree the page is wrong, not the brief. Confirm on the sheet that the peak is the largest visual change and holds the most scroll room, and that the last screen resolves instead of fading to nothing.

And say what a green run does not cover: a real phone. Headless Chrome cannot reproduce an iPhone's video decoder, autoplay policy, Low Power Mode, or touch scrolling; a build once shipped four green rounds while the hero clip sat frozen on the actual device. Mobile is a first-class target throughout, not a pass at the end: portrait phone clips, touch-tuned lerp, grown tap targets are all authored (see assets.md and verify.md). When any mobile defect is reported, deploy references/device-diag.html beside the site on the first round and let the device answer, rather than theorising from a machine that cannot reproduce the failure. The full iOS clip-lifecycle notes live in verify.md, "The phone is a different machine".

Fix what you found and shoot it again. Report what you actually verified and what you did not.

Hard rules

Ship-blockers, not preferences. Each one is a thing that makes a page read as machine-made.

Output

The build folder, including BRIEF.md, then a short report: the grammar and why the other seven lost, the signature move, the fingerprint gate result against each existing row, the journey, the feeling curve and the peak, the feel-check diff (intended curve against felt curve, and what you changed), the score table (device per beat), what you generated, what you verified with screenshots, and anything you could not verify. Say if the brief was self-authored rather than interviewed. Give the local URL. Keep it brief; the page is the deliverable.

Then append the build's row to <workspace>/FINGERPRINTS.md.

Changes to the skill itself, and the build findings that drove them, are logged in CHANGELOG.md.