The HyperFrames composition contract — build one renderable project. Use for composition structure, the `data-*` timing attributes, `class="clip"`, tracks, sub-compositions, variables, framework-owned media playback, deterministic-render rules, and validation. Also covers Tailwind projects and the S

HyperFrames Core HyperFrames renders video from HTML. A composition is an HTML file whose DOM declares timing with data attributes, whose animation runtime is seekable, and whose media playback is owned by the framework. This skill is the technical contract — how to build one hyperframes project. The body below is the build guide; per topic detail lives in references/ (index next), read on demand. Other concerns live in the sibling domain skills — hyperframes animation , hyperframes creative , media use , hyperframes cli , hyperframes registry . The capability map in /hyperframes says what each one covers. References File Read it to… references/minimal composition.md start from the smallest renderable composition skeleton references/composition patterns.md choose monolithic vs modular; structure a modular index.html ; pick a sub comp archetype references/data attributes.md look up any data (root / clip / sub comp host / legacy aliases); use class="clip" references/tracks and clips.md understand what data track index does (and does not) control, z index, time a clip relative to another references/creator editing recipes.md copy truthful cut/trim/reorder/retime/freeze/camera/mask/crossfade/audio editing recipes and their limits references/sub compositions.md wire a sub composition (host attrs, <template , per instance vars) and animate inside it references/variables and media.md declare variables; place <video / <audio , set volume, trim references/determinism rules.md build a seekable timeline; determinism bans; layout / text fit references/full screen motion.md author full frame motion with shared backgrounds references/storyboard format.md author a STORYBOARD.md plan (+ the parsed manifest) references/review loop.md run the plan → sketch → build review passes on a live board — shared by every storyboard planning workflow references/production loop.md take an approved plan to a delivered video — the stage dependencies (audio, frames, assembly, transitions, captions, verify, deliver) a freeform build follows directly references/brief contract.md the brief's ground rules — mode derivation (collaborative / autonomous), shared field registry, question invariants (the asking itself lives in /hyperframes → the intent layer) references/brief format.md author BRIEF.md — the confirmed intent document a workflow's Setup writes and every later step reads references/script format.md author the optional SCRIPT.md locked narration references/subagent dispatch.md map subagent dispatch verbs (parallel fan out / background / wait) to your harness references/frame worker core.md the shared frame worker role contract — each narrative workflow's packet builder prepends it to that workflow's sub agents/frame worker.md delta references/tailwind.md work in a Tailwind v4 project ( init tailwind ; runtime contract differs from Studio's v3) For animation runtime specifics (GSAP API, Lottie, Three.js, etc.) go to hyperframes animation → adapters/<runtime .md . Building a composition Two root forms (not interchangeable) Standalone (top level index.html ): root <div data composition id="…" sits directly in <body , no <template wrapper . Wrapping a standalone root hides all content and lint rejects it ( standalone composition wrapped in template , error). Sub composition (loaded via data composition src ): wrap the root in <template . This is the shape to write: the loader also accepts a plain full document and falls back to its <body , but the templated form is what the examples and tooling assume. ⚠ Transport rule: for a templated sub composition the assembler drops the file's own <head <style / <script ( packages/core/src/compiler/compositionAssembly.ts , the hasTemplate gate), so put <style / <script inside the template. <link is hoisted either way. ⚠ Host id convention: give the host slot, the inner template, and the window. timelines["<id "] key the same id. A different local id is supported (the assembler falls back to the first root in the file) but the mismatch is silent, so match them unless you have a reason not to. File shape, host wiring, and the pre render checklist → references/sub compositions.md . Root must be sized (silent layout bug) The standalone root needs an explicit sized box ( width / height in px), and every ancestor down to a height:100% element must have a resolved height — otherwise a flex/ 100% child collapses to ~0 and content piles into the top left corner. Do not rely on automated gates alone to catch this; inspect a snapshot. Skeleton → references/minimal composition.md . One paused timeline Each composition registers exactly one gsap.timeline({ paused: true }) at window. timelines["<id "] (key = root data composition id ). Building it inside an async callback ( document.fonts.ready ) is supported; what matters is that you register only after the build completes . Render length is the root's data duration , not the timeline's length: a timeline that runs past it is cut off, and one that ends early holds its last frame. Omit the root data duration and the length is inferred instead (timeline, media window, or adapter). You do not need window. timelines = window. timelines {} : the runtime creates the registry before your inline scripts run, and lint no longer asks for it. Don't manually nest sub timelines into the host; the runtime auto nests registered child timelines. Full contract (incl. non GSAP runtimes) → references/determinism rules.md + hyperframes animation/adapters/ . First pass lint gotchas (a guaranteed first build failure) Rules that lint does catch, but only after the fact. Write them right the first time: Never pair a CSS initial transform with a GSAP tween on the same property — the CSS value and the tween's start fight and lint rejects it with gsap css transform conflict . Set the initial state inside the tween with gsap.fromTo(el, { x: 40 }, { x: 0 }) instead of a CSS transform: translateX( 40px) . Never put crossorigin on <video / <audio . lint rejects it unconditionally with media crossorigin breaks preview (error), including for canvas/WebGL/WebAudio readback. There is no suppression. Never give a <video data start an ancestor that also carries data start . lint rejects it with video nested in timed element (error). Time the wrapper or the video, not both. Every <audio needs an id . lint rejects it with media missing id , and an id less <audio is never picked up by the mixer, so the render is silent . A lint error also switches off the layout and contrast audits: check then reports 0 sample(s) and 0/0 text checks , which reads like a clean file but means nothing ran. Clear lint errors before you trust those numbers. Non negotiable rules (silent bugs automated gates may miss) Surfaced here; full rationale in the linked reference. Do not violate: No render time clocks / unseeded Math.random / network / input state; no repeat: 1 (use a finite count). → determinism rules.md Never tween display or raw visibility on a clip element. The framework owns clip visibility, and lint rejects it. Use GSAP autoAlpha or a zero duration boundary set . (Tweening ordinary visual properties on a clip element is fine; what lint forbids is taking over its visibility.) → determinism rules.md No <br in body text; transformed elements must be block level + sized; pulsing absolute decoratives need peak clearance. → determinism rules.md <video / <audio are found by a flat document query, so the framework seeks and decodes them at any nesting depth (including inside a sub comp <template or wrapper). One hard limit: lint errors if a <video data start sits inside another plain element that also has data start , and the failure is real (wrong source frames, then the clip vanishes mid slot), so put the timing on the wrapper or on the video, never both. Sub composition hosts are exempt: media inside a sub composition renders correctly. The other caveat is timelines, not placement: a sub comp timeline can't animate host root elements. → variables and media.md Keep every id unique across the assembled page (prefix sub comp ids with the composition id, <id hero ) so your own id CSS and getElementById calls resolve. Frame injection no longer depends on it: the compiler stamps a document unique data hf render id on every video[src] / audio[src] / img[src] . Media that uses <source children instead of a src attribute is not stamped, so unique ids still matter there. → composition patterns.md A full screen fill on the composition root is fine on a normal render. It is dropped only on the layered composite path (HDR content, or a composition using shader transitions), where the engine forces every composition root transparent so the layer beneath shows through. If your composition uses shader transitions or HDR media, put the fill on a full bleed child ( position:absolute; inset:0 ). → composition patterns.md Editing existing compositions Read the files first. Preserve unrelated timing, tracks, IDs, variables, media paths. Match existing composition IDs and timeline keys. Adding a clip: set its data start / data duration intentionally against the clips around it. data track index is a Studio display lane, not a timing constraint, so it does not need to be free. data hidden on any composition element hides it in BOTH preview and render, overriding its time window; it is non destructive/reversible and toggled by Studio's timeline eye icon. Adding a sub composition: verify its internal data composition id before wiring the host. Validation Use hyperframes cli for command details [ ] npx hyperframes check passes (0 findings across lint, runtime, layout, motion, and contrast) [ ] Projects with sub compositions:

hyperframes-core