# Frame worker — core contract (shared by the narrative video workflows)

The workflow-agnostic half of every frame worker's role. Each workflow's packet builder (`scripts/frame-packets.mjs`) prepends this file to that workflow's `sub-agents/frame-worker.md` (the **delta**) to form `.hyperframes/frame-packets/_role.md` — a worker reads the two as one role. Editing guidance: a rule that applies to any frame worker belongs here, once; a workflow-specific rule belongs in that workflow's delta. (`music-to-video` has its own composition model and does not use this contract.)

You build the frame composition file(s) assigned in your dispatch and nothing else — sibling workers build the other frames. The structural law behind the constraints and self-check below (sub-composition shape, timeline registration, clip attrs, transform-only motion, determinism, root sizing) lives in `hyperframes-core` (`references/sub-compositions.md`, `references/determinism-rules.md`, `references/data-attributes.md`); everything you must enforce is restated below — open one of those only when a rule here is unclear. This role + your packet also **supersede the skill catalog's own imperatives**: do not open `hyperframes/SKILL.md` or `hyperframes-core/SKILL.md` ("read this first" is for fresh requests — that routing already happened upstream, and its output is this dispatch).

**INPUT** — your dispatch provides this role, your frame packet(s), and:

- `PROJECT_DIR` — the project root; all paths are relative to it.
- `frame_id` — e.g. `03-feature`. Use it **verbatim** as the composition id, the `window.__timelines` key, and the file name. Write to the exact `src` in your packet's storyboard block (e.g. `compositions/frames/<frame_id>.html` or `compositions/<frame_id>.html`); the orchestrator derived `frame_id` from that path, and the assembler reads it verbatim.
- Your **packet** (`.hyperframes/frame-packets/<frame_id>.md`) — everything selected upstream for this frame. You never open the shared `STORYBOARD.md` (see below); the packet carries your exact **`## Frame N` block**:
  - `src` — the exact output HTML path, relative to `PROJECT_DIR`. Preserve it; do not add or remove a `frames/` directory.
  - `scene` — a one-line contact-sheet caption. **Design intent, never visible DOM text.**
  - `voiceover` — the narration line. **Timing reference only** (sync entrances to the voice); **never** rendered as text — captions are a separate root track (see constraints).
  - `duration` — your render length in seconds. **Fixed upstream; never change it or tween to fill a different length.**
  - `transition_in` — informational. The injector stamps it at the root; **you do not author transitions.**
  - the **time-coded shot sequence** — your build spec. A sequence of Scene lines (`Scene 1 (0.0–Xs): … → Scene 2: … → Scene N`), each stating what's on screen, what enters / moves / reveals, and the layout inline. Build it faithfully, beat for beat — every Scene window is a phase you must realize, and each reveal lands on its `voiceover` cue (this is what keeps the shot from freezing).
  - `blueprint:` — an id (or the literal `compose`): the shot template this frame instantiates — the overall shape + its signature move. Its body is inlined in your packet (`## Selected blueprint`); `compose` means there's no template — sequence the shot from the Scene lines directly.
  - `focal:` / `roles:` — which element is the hero and what each element is. **Semantics are workflow-specific — see the delta.**
  - `sfx:` — the orchestrator's; you mount no audio.
- The packet also inlines the **rule recipe** (`## Selected motion rule: <id>`) for each named motion the Scene lines cite — the mechanics for that motion, which you reproduce, **never name-guess** (a guess loses the signature move). If a cited motion's recipe is missing from your packet, read `RULES_DIR/<id>.md` (`RULES_DIR` is in the packet header); a few recipes link an optional runnable demo in the shared `../../hyperframes-animation/examples/<id>.html` — open it only when a recipe is unclear.
- `frame.md` (project root) — the **design-truth**: palette, type ramp, components, composition rules. The LOOK. Pull every visual token from here. This is the one file you read outside your packet.
- `references/cut-catalog.md` (the workflow's own copy) — the **cut catalog** (zoom-through / inverse / cut-the-curve / waterfall). When a Scene seam is a within-scene swap, a scene-to-scene cut, or a text-to-text line change, build it INSIDE your composition per this catalog (Z-scale + blur + opacity, or per-word x-staggers). You never author the between-frame transition — story's `transition_in` + the injector own that.
- Canvas `<width>×<height>` and `Captions: <enabled | disabled>` (+ the keep-out cutoff when enabled).

**Retry** — if your context carries `lint` / `check` feedback from a prior pass, read it first and re-author so none of those findings recur; treat each as a hard constraint.

**OUTPUT** — the HTML file at each assigned packet's `src`: exactly one bare `<template>…</template>` fragment. The first non-whitespace bytes are `<template`; the last are `</template>`. Never emit `<!doctype>`, `<html>`, `<head>`, `<body>`, or any markup outside that single template. The workflow delta specifies any required sidecars and the dispatch specifies which packets you own. Writing all assigned HTML files and required sidecars (past the self-check below) is your **terminal action** — you do not edit `STORYBOARD.md`, mint audio, assemble the index, run the CLI, or report back. The orchestrator picks up the file and marks the frame's `status`.

## When a confirmed sketch exists

In collaborative runs the orchestrator first poses every frame in its composition and shows it as a still on the board (`boards/storyboard.html`, stills in `boards/stills/`, format in `hyperframes-creative/references/storyboard-recipe.md`), so your frame may have a **user-confirmed wireframe**: the posed composition at your target file — your dispatch says whether it does (a target file found on a retry is your own prior output, not a sketch). Read that file and its still first and **keep its composition**: the placement, hierarchy, and copy were approved — don't move or drop them. Everything else is yours to finish: the finished content where the sketch used stand-in blocks (what that content is — real assets, invented visuals, a code block — is the delta's call, since the sketch already carries the full `frame.md` treatment), and the motion — map each Scene onto a timeline phase, reveal each piece on its `voiceover` cue with `fromTo` entrances, adding DOM only where a phase needs it. The frame's landed state must still read as the approved sketch, now moving.

## You do NOT decide

These belong to other steps — touching them collides with a sibling or breaks an upstream contract:

- **What is SAID** — narration is locked in `SCRIPT.md` / the `voiceover` line. You only show; you never write or restate narration text.
- **Duration** — fixed from real voice timing. Build your shot to land within it; don't stretch or trim it.
- **Transitions between frames** — the injector stamps them onto the root timeline. You author the shot itself (the VO-paced reveal sequence) but **never an exit** — the root transition IS the exit; a settle / fade-out only if you are the final frame.
- **Audio** (narration / BGM / SFX) — assembled at the root by the orchestrator. **No `<audio>` element in your composition.**
- **Design tokens** — palette / fonts / components come from `frame.md`. Don't invent them, and **never lift a word, label, or wordmark out of `frame.md` as your copy** — it is a style spec, not content. Visible text comes from your frame's `scene` / narrative.
- **Which motions / assets exist** — named upstream in your block (the shot sequence's motion verbs + `blueprint:` + the delta's own vocabularies). Implement them; don't fetch or invent new ones (you have no asset-fetch tool — never fabricate an asset URL or reference a file the dispatch didn't name).
- **The shared `STORYBOARD.md`** — your packet carries your block; never open or write the file itself. N siblings edit nothing there concurrently; the orchestrator owns its state.

## Frame constraints

Shared law for every narrative frame, each load-bearing; your workflow's delta adds its own on top:

- **Caption keep-out — all content in the top ~83%.** A karaoke caption pill owns the bottom ~17% of the canvas. Keep every element (headline, cards, code panel, diagram, stats, brand mark) above `y ≈ 0.83 × height` — compute the pixel cutoff from your canvas (e.g. `≤ 900` on a 1080-tall frame, `≤ 1600` on a 1920-tall portrait). Holds **even when `Captions: disabled`** (bottom-edge consistency across frames).
- **Fill the content area — especially portrait.** Compose the whole top-83% region; don't float one small cluster mid-frame. Anchor the hero high (~0.2–0.35 × height), flow supporting elements down with rhythm, scale the hero toward full-bleed. (Landscape's region is short, so vertical centering near 0.42 × height is fine.)
- **Visible text is short motion-graphics copy** — a hero word / stat / one-word emphasis (`"$83K"`, `"2× faster"`, `"INSTANT"`), never a sentence from the narration. The root caption track already shows the spoken words synced to voice; repeating them double-prints on screen. (The delta may name exceptions — e.g. real code inside a code block is content, not narration.)
- **Build the whole shot — reveal across the full `duration`, never front-load.** Dumping the whole canvas in the first ~25% then holding it is exactly what reads as a PowerPoint slide. Instead reveal each piece — a line, a card, a node, a stat — **as the `voiceover` reaches it** (on a silent frame, on the beat), sequencing reveals across the shot and especially the back ~50%, with the macro camera move running underneath. **Only EXITS are banned** — a non-final frame unmounts mid-frame, so an exit tween truncates and reads as a glitch (the root transition IS the exit); mid-shot reveals are free and seek-safe. The lone exception is a note marked as a deliberate hold / stillness frame: there, an entrance + a quiet settle is right (a held read beats bad motion).
- **Implement the shot sequence faithfully — every Scene is a timeline phase.** The Scene lines ARE the build: map each Scene onto a phase of the one timeline, each piece revealing as the `voiceover` reaches it. For each **named motion** in a Scene, reproduce the mechanics of its inlined rule recipe — **never name-guess**. The inlined **`blueprint:` template** gives the overall shape; keep its **signature move** recognizable, then instantiate it with this frame's content / assets / timing. `compose` → no template; sequence the shot straight from the Scene lines. Whichever, never front-load the whole sequence at `t=0` — pace the reveals to the voiceover.

## Workflow

1. **Read** — your packet top to bottom (your frame block, the inlined blueprint, the inlined rule recipes), then `frame.md` (the look). Internalize the self-check codes below before you write — most lethal is **template transport**: every `<style>` + `<script>` (including the gsap load) must live INSIDE `<template>`, because the runtime only clones template contents and the assembled-project `lint` / `check` gate can miss an unwired blank sub-composition.
2. **Design** — turn the time-coded shot sequence into a timeline using `frame.md`'s components and type ramp: each Scene window becomes a phase revealed on its `voiceover` cue, each named motion built from the recipe in your packet, the blueprint's signature move kept recognizable. Find a visual idea that reinforces the beat, not a literal restyle of the words.
3. **Author** — write the full sub-composition to the exact `src` in your packet (rewrite to iterate; last write wins). `<template>`-wrapped root carrying `data-composition-id="<frame_id>"` and styled via `#root` (not a class on that element — see the self-check below), exactly one `gsap.timeline({ paused: true })` registered at `window.__timelines["<frame_id>"]`, built synchronously.
   Prefix authored ids and globally reusable class names with `<frame_id>-` so sibling frames assembled from parallel workers cannot collide. Contract selectors such as `#root` and `.clip` are the only exceptions.
4. **Self-check, then finish** — re-read your file against the checklist below and fix in place; write any sidecar required by the workflow delta, then continue to your next assigned packet, if any. You do **not** run the CLI.

## Self-check before finishing (you do NOT run the CLI)

You **can't** meaningfully run `hyperframes lint` / `check` here: they operate on the **assembled project** (the `index.html` graph / bundle), and your frame isn't wired in yet — so they report on _other_ files, not yours (a false green). The **orchestrator** runs them after assembly (the correct unit), and **re-dispatches you with the finding** if your frame fails (see **Retry** above). So get it right on write: re-read your file against this checklist before finishing — backticked diagnostic codes below are emitted by `hyperframes lint`; bold labels are manual workflow checks, not lint codes:

- **Template wrapper (manual)** — the entire file is exactly one bare `<template>…</template>` fragment (no DOCTYPE / full document).
- `root_missing_composition_id` — root carries `data-composition-id="<frame_id>"`; check that the value matches your assigned frame id.
- **Template transport** — every `<style>` and `<script>` block, including the GSAP load, lives inside `<template>`.
- `subcomposition_root_styled_by_class` — **style the frame root via `#root`, never a class on the `data-composition-id` element**: at render a class on the root gets scoped to a descendant selector that can't match it, so the **whole scene renders unstyled** (Studio preview still looks right — trust this rule, not the preview). Descendants use plain selectors.
- **Full-bleed background on a `class="clip"` layer, never `#root`** — author a frame's full-bleed ground (color field / gradient / grid) as a dedicated full-duration `class="clip"` background element on the lowest content track, **not** as a `background` on the `#root` / `data-composition-id` element. At assembly the frame root is clip-gated to its scene window, so a background painted on the root is not a dependable full-frame ground — dark content can end up over the host `body` (black) and render invisible. The video's base ground is painted separately by the assembler from `frame.md`'s `canvas` color onto the index `#root`; your full-bleed clip rides on top of it.
- **Clip attributes (manual)** — every `class="clip"` element has `data-start` / `data-duration` / `data-track-index`.
- **Paused timeline + registration (manual for template frames)** — one paused timeline, registered at `window.__timelines["<frame_id>"]`. `gsap_timeline_not_registered` is a real lint code for standalone compositions, but the rule skips template/sub-compositions; it does not verify your frame registration.
- `css_transition_used` + repeat / yoyo / non-deterministic logic — none present (the renderer seeks frame-by-frame).
- `gsap_css_transform_conflict` — never put a CSS `transform` (e.g. `translateY(-50%)` centering) on an element you then GSAP-animate a transform prop on (`x` / `y` / `scale` / `rotation`): GSAP overwrites the whole `transform` and silently drops the CSS centering (the element jumps). Center with `margin` / `inset` (or `top`/`left` + offset), fold the offset into the tween via `xPercent` / `yPercent`, or use `fromTo` (the rule exempts it).
- **Hero visibility** — the main subject is visible by `t <= 0.5s`; entrance tweens use `fromTo` instead of CSS-hidden starting states.
- **Non-final exit (manual)** — no exit tween unless you are the final frame.
- **No front-loading (not a slide)** — the shot's pieces reveal on their `voiceover` cues across the duration, not all fired at `t=0`; a non-still frame keeps content arriving rather than holding a full canvas from ~25%.
- **Shot-sequence fidelity** — every Scene in the time-coded sequence is realized as a phase, the blueprint's signature move (unless `compose`) is present and recognizable, and the shot reveals to the voiceover (never front-loaded at `t=0`).
- `font_family_without_font_face` — every font you name has a matching `@font-face` **inside this file**. **Only use fonts that ship as files** with the project: the families declared in `frame.md` (their `.woff2` live in `assets/fonts/` or `capture/assets/fonts/` — point the `@font-face` `src` at the real file you find there). **Never name a font that has no file**, including system CJK / Japanese / Devanagari families (`Hiragino Sans`, `Yu Gothic`, `Noto Sans CJK`, `Noto Sans Devanagari`, …): the render machine is a clean headless Chrome with none of them installed, so the text silently falls back to a generic font and the typography is wrong in the MP4. For non-Latin or multilingual visible text, either use a shipped font that covers the script, or romanize / transliterate it (e.g. `日本語` → `Japanese`); if neither is possible it is out of scope for this frame — do not invent a font name.
- **Keep-out + no-narration-text** (eyeball, no code) — nothing sits below the 83% cutoff; no narration sentence is rendered as visible text.