/hatch-pet

name: hatch-pet
description: Create, repair, validate, preview, and package Codex-compatible animated pet spritesheets from character art, screenshots, generated images, or visual references. Use when a user wants to hatch a Codex pet, create a custom animated pet, or build a built-in pet asset with an 8x9 atlas, transparent unused cells, row-by-row animation prompts, QA contact sheets, preview videos, and pet.json packaging. This skill composes the installed $imagegen system skill for visual generation and uses bundled scripts for deterministic spritesheet assembly.
triggers:
  - "hatch a pet"
  - "hatch pet"
  - "codex pet"
  - "spritesheet pet"
  - "animated pet"
  - "孵化宠物"
  - "电子宠物"
od:
  mode: image
  surface: image
  scenario: personal
  preview:
    type: image
    entry: final/spritesheet.png
  design_system:
    requires: false
  outputs:
    primary: final/spritesheet.png
    secondary:
      - final/spritesheet.webp
      - pet.json
      - qa/contact-sheet.png
  example_prompt: "Hatch me a tiny pixel-art shiba pet — friendly, sitting upright, with a small pomegranate prop. Use the hatch-pet skill end-to-end."
  upstream: "https://github.com/openai/skills/tree/main/skills/.curated/hatch-pet"

Hatch Pet

> **OpenDesign integration.** This is the unmodified Codex `hatch-pet` skill, > vendored under `skills/hatch-pet/` so any OpenDesign agent can run it. After > the skill finishes packaging, the resulting `spritesheet.webp` (under > `${CODEX_HOME:-$HOME/.codex}/pets/<pet-name>/`) can be imported into the > floating pet companion via **Settings → General → Pets → Import Codex sprite**. The > import flow auto-detects the 8×9 / `192×208` atlas and lets the user pick > which animation row to play (idle, running-right, waving, …).

Overview

Create a Codex-compatible animated pet from a concept, one or more reference images, or both. This skill owns pet-specific prompt planning, animation rows, frame extraction, atlas geometry, QA, previews, and packaging. It delegates visual generation to `$imagegen`.

User-facing inputs are optional. If the user omits a pet name, infer one from the concept or reference filenames; if that is not possible, choose a short appropriate name. If the user omits a description, infer one from the concept or references. If the user omits reference images, generate the base pet from text first, then use that base as the canonical reference for every animation row.

Generation Delegation

Use `$imagegen` for all normal visual generation.

Before generating base art, row strips, or repair rows, load and follow the installed image generation skill:

${CODEX_HOME:-$HOME/.codex}/skills/.system/imagegen/SKILL.md

Do not call the Image API directly for the normal path. Let `$imagegen` choose its own built-in-first path and its own CLI fallback rules. If `$imagegen` says a fallback requires confirmation, ask the user before continuing.

When invoking `$imagegen` from this skill, pass the generated pet prompt as the authoritative visual spec. Do not wrap it in the generic `$imagegen` shared prompt schema and do not add extra polish, hero-art, photo, product, or illustration-style augmentation. Pet prompts should stay terse, sprite-specific, and digital-pet oriented; only add role labels for input images and any essential user constraint.

Use this skill's scripts for deterministic work only: preparing prompts and manifests, ingesting selected `$imagegen` outputs, extracting frames, validating rows, composing the final atlas, creating QA media, and packaging.

Hard boundary: do not create, draw, tile, warp, mirror, or synthesize pet visuals with local Python/Pillow scripts, SVG, canvas, HTML/CSS, or other code-native art as a substitute for `$imagegen`. For a normal pet run, expect up to 10 visual generation jobs: 1 base pet plus 9 row-strip jobs. The only exception is `running-left`, which may be derived by mirroring `running-right` only after `running-right` has been generated, visually inspected, and explicitly approved as safe to mirror. If mirroring is not appropriate, generate `running-left` as a normal grounded `$imagegen` row. If those calls are too expensive, blocked, or unavailable, stop and explain the blocker instead of fabricating row strips locally.

Do not mark visual jobs complete by editing `imagegen-jobs.json`, copying files into `decoded/`, or writing helper scripts that populate row outputs. Use `record_imagegen_result.py` for selected built-in `$imagegen` outputs, or `generate_pet_images.py` only for the documented secondary fallback. The deterministic scripts may only process already-generated visual outputs.

Only the base job may be prompt-only. Every row-strip job generated through `$imagegen` must use the input images listed in `imagegen-jobs.json`, including the canonical base reference created after the base job is recorded. Treat any row generation without attached grounding images as invalid.

Codex Digital Pet Style

Default pet art should match the Codex app's built-in digital pets: small pixel-art-adjacent mascots with compact chibi proportions, chunky readable silhouettes, thick dark 1-2 px outlines, visible stepped/pixel edges, limited palettes, flat cel shading, simple expressive faces, and tiny limbs. Even if the reference art is more detailed, complex or realistic, the generated pet should be simplified into this style.

Do NOT generate polished illustration, painterly rendering, anime key art, 3D rendering, glossy app-icon treatment, realistic fur or material texture, soft gradients, high-detail antialiasing, and complex tiny accessories. References that are more detailed than this should be simplified into the house style before row generation.

Transparency And Effects

Pet rows are processed into transparent 192x208 cells, so every generated pixel must either belong to the pet sprite or be cleanly removable chroma-key background. Prefer pose, expression, and silhouette changes over decorative