Mascot Window

---
name: mb-mascot-window
description: A window opens in a page, a character climbs in, waves, points at the headline with a long arm, then ducks away and the shutters close. Use it to give a launch line or a sign-off some personality. Renders one 1920x1080 30 fps H.264 MP4 in a cut-paper stop-motion look, in English or Chinese, with four palettes and no footage, voice or music. Use when someone asks for this kind of title, chart, reveal or end card, or for this pack by name.
version: 1.0.0
---

# Mascot Window

A window opens in a page, a character climbs in, waves, points at the headline with a long arm, then ducks away and the shutters close. Use it to give a launch line or a sign-off some personality.

Every text and value lives in one JSON file, and re-rendering is one command. The look lives in `assets/`. Your job is to fill the fields, never to restyle. Exact tokens and timings are in `references/style.md`.

## Inputs to ask for

Ask once, in one message, for what the brief does not give:

1. A headline. A sub line, an action and a transparent PNG of your character are optional.
2. The user's own text or facts. Paste them unchanged into `"source"`.
3. Language: `en` or `zh`. One language per version; for both, make two JSON files.
4. Palette: `vermilion`, `cobalt`, `pine` or `apricot`. If nobody says, use pine.

**No answer comes:** proceed, and list your assumptions at the top of your reply.

## Steps

1. Write `clip/beats.json` in a new folder. `assets/library.json` and `assets/library.zh.json` are valid filled examples: copy the shape, not the fictional words.
2. Validate: `node <skill>/scripts/check.mjs clip/beats.json`. Fix everything it reports.
3. Look before rendering: `node <skill>/scripts/sheet.mjs clip/beats.json clip/sheet.png --at 0.99`, then view the image. Try `--at 0.5` as well.
4. Render: `node <skill>/scripts/render.mjs clip/beats.json --out clip --flat`.
5. Check what a viewer sees: `node <skill>/scripts/check.mjs clip`. Fix the JSON, re-render, and check again until it passes.
6. Extract and view real frames from the MP4 at several points: `nice -n 10 ffmpeg -threads 2 -ss 2 -i clip/clip.mp4 -frames:v 1 f.png`. The checker cannot judge whether it looks right. You can.

`--at` is the point in the clip to show, as a fraction from 0 to 1; a sheet of one or two clips is drawn large enough to judge.

Options: `--only clip --frame 120` re-renders one frame to `clip/frames/clip-120.png`. `--stills 0.3,0.6,1` writes stills to `clip/frames/`. `--scale 0.5` makes a draft at `clip/draft/clip.mp4`, even with `--flat`, and the checker refuses drafts. Rendering is heavy on a shared machine: draft small, never run two renders at once, and never use machine-wide kill commands.

`check.mjs` runs from wherever the skill is installed. Give it a JSON file, a folder (with `--beats path/to/beats.json` if the JSON is elsewhere) or any MP4. To run every check on a renamed MP4, add `--beats`. `check.mjs --test` is a short self test. It catches: an opaque mascot picture (at JSON validation), a fingertip that misses the headline, a headline under the window, overflow, frozen clips, an empty headline, wrong size or codec, and placeholders.

## beats.json

```json
{
 "lang": "en",
 "palette": "pine",
 "label": "Fictional example",
 "source": "Fictional example: a bakery that has fresh rolls by six.",
 "beats": [
  {
   "id": "clip",
   "job": "close",
   "effect": "mascot-window",
   "seconds": 8,
   "slots": {
    "headline": "Fresh rolls by six",
    "sub": "A fictional bakery, for this example only",
    "action": "Order by noon"
   }
  }
 ]
}
```

| Field | Meaning | Limit | Thin brief |
|---|---|---|---|
| `lang` | Language of all text on screen | `en` or `zh` | Use the language of the source |
| `palette` | The one colour setting | One of the four | pine |
| `label` | Small tag on the clip | 30 characters, optional | Fictional example for samples, or 虚构示例. Leave it out for real work |
| `source` | The user's text, unchanged. Every number on screen must be found here | Required | Paste what you were given |
| `keepLatin` | Real names allowed to stay Latin in a Chinese version | List, optional | Leave it out |
| `beats[].id` | Clip file name | Letters, digits, hyphen | clip |
| `beats[].job` | Keep as shown | `close` | `close` |
| `beats[].effect` | Keep as shown | `mascot-window` | `mascot-window` |
| `beats[].seconds` | Clip length | 6 to 9 | 8 |

## Every field in slots

| Field | Meaning | Limit (characters) | Thin brief |
|---|---|---|---|
| `headline` | The line the character points at. Required. | 44, required | Use the main line of the script. |
| `sub` | Smaller line under the headline. | 70, optional | Leave it out: the headline grows. |
| `action` | What the viewer should do, on a dark plate. | 24, optional | Use the ask in the script. None: leave it out. |
| `mascot` | Object: {"src":"character.png"}, a transparent PNG with its face in the upper two thirds, relative to the JSON. The bottom eighth sits behind the sill. | PNG, optional | Leave it out: an original cut-paper creature appears. Never use a known mascot without the rights. |

## Rules

**Your character:** a transparent PNG in `mascot`, with its face in the upper two thirds, since the bottom eighth sits behind the sill and the character is sized by what is drawn, not by empty margin. Any transparent PNG works, including exports from Clay Buddy, the character-maker pack on this site. Paper mitts and arms with a round shoulder are added, since a flat PNG has none; they sit on top of the character and can look added on. An opaque PNG fails `check.mjs` on the JSON, before you render. **With none:** an original cut-paper creature with blinking eyes appears; it owes nothing to any known mascot. Never supply a known mascot without the rights. **The arm** always reaches the end of the last line of the headline, however long the headline is; the check measures the fingertip against the headline. **Product name:** put it in the headline, or in `label` as Fictional app: Name. Empty `sub` and `action` leave things out, and the headline grows to fill the column.

**Generate no invented numbers.** Every figure must be in `source`, and the checker fails any that is not. **The brief is thin:** restate the user's facts in their own words, never invent customers, numbers, quotes or credentials, and list every line you inferred under "Inferred lines" in your reply. **Nobody can answer:** proceed and list your assumptions. **Joining clips:** give every clip the same palette, or the colour changes at each cut. **A different length is wanted:** change `seconds` within the range. **No real link:** do not show an address. **Line breaks:** words are kept whole; if a break reads badly, put `\n` in the text.

## Deliverables

`clip/beats.json`, the one file to edit, and `clip/clip.mp4`: 1920x1080, 30 fps, H.264, yuv420p, silent. Add a note with assumptions, inferred lines and the re-render command.

## Render time

Measured on a 16 GB Mac with other work running, at low priority and full size: 6 s for this 8-second clip with its default material.

## Before delivering

- [ ] `check.mjs` on the folder exits 0. Quote its last line.
- [ ] You viewed real frames from the final MP4 at several points.
- [ ] Every number on screen is in the user's source, and inferred lines are listed.
- [ ] One language per version.
- [ ] Fictional material is labelled through `label`.
- [ ] No footage, voice or music was generated.

## When not to use it

The tone is serious or the subject is sensitive: a waving creature will undercut it. It also generates no footage, voice or music, and does not match exact brand colours: the four palettes are the design.

## Requirements

- Node 18 or later, and ffmpeg with ffprobe on the PATH or in /opt/homebrew/bin.
- Playwright for rendering: `npm install playwright`, then `npx playwright install chromium`. If it is installed elsewhere, set `NODE_PATH` to that `node_modules`. `check.mjs` needs no packages.
- Fonts are system stacks. Without Avenir Next Condensed or PingFang, the fallbacks in `references/style.md` apply and the text is re-fitted. Run the check there.