hatch-pet: OpenAI's skill for making a custom Codex pet

• Looks up brand cues on the web when you give only a company name

  Optional. If you give a description or pictures instead, this step is skipped.

  Try: “$hatch-pet make a pet for Stripe”

  Network · Brand discovery

• Sets up the run folder, prompts and layout guides, and picks a name and style

  Chooses a name (Sprout by default), a style preset and a background color for cutting the art out, then writes the job list.

  Files · prepare_pet_run.py

• Generates the main look of your pet with Codex's image skill

  One picture of the pet that every animation row is drawn from.

  Network · Base image

• Generates one strip per state: idle, running, waving, jumping and more

  Up to 10 image jobs in total, one base plus nine rows, with at most two running at once.

  Network · Nine animation rows

• Mirrors the running-right row into running-left

  Used only after the right-facing row looks safe to flip.

  Files · derive_running_left_from_running_right.py

• Cuts each strip into 192x208 pixel frames

  Has a stable-slots mode that stops the pet from changing size between frames.

  Files · extract_strip_frames.py

• Flags frames with stray edge pixels, empty frames or leftover background color

  Writes a review file that the visual check reads.

  Read · inspect_frames.py

• Builds the 1536x1872 sprite sheet as PNG and WebP

  A grid of 8 columns by 9 rows, one row per pet state.

  Files · compose_atlas.py

• Checks the sheet size, grid and empty cells

  Writes a validation report next to the finished sheet.

  Read · validate_atlas.py

• Makes one labeled overview image of every frame for review

  Lets you and the skill spot drift in the pet's look.

  Files · make_contact_sheet.py

• Makes a GIF preview for each pet state

  Saved in a previews folder so you can watch each animation.

  Files · render_animation_previews.py

• Reviews previews for look drift, wrong direction and popping, then redraws only the bad ro

  You do not have to restart the whole pet to fix one animation.

  Try: “$hatch-pet repair the waving row of my pet Sprout”

  Network · Visual check and repair

• Saves pet.json and spritesheet.webp into your Codex pets folder, then cleans up

  Pick the pet afterwards in Settings > Pets.

  Files · Package

Watch out for

• Brand names trigger a web search

  Snyk rates this Warn (medium) because the skill reads outside web pages to find brand cues. Give a description or pictures instead if you want no web search. skills.sh

• It deletes its own generated images and run files

  After copying each picked image it removes the original from ~/.codex/generated_images, and it clears working files after checks. Ask to keep debug files if you want them. github.com

• Create pet has overwritten an installed hatch-pet folder

  Users report the app replacing a hatch-pet folder installed another way, and deleting it on some Windows builds. Back up the folder before you click Create pet. github.com

• Failed image attempts can still use your quota

  A user reports that failed image generation on Windows still counted against usage. Watch your usage if generation keeps failing. github.com

• Runs eight local Python scripts

  They use Pillow to cut frames, build the sheet and make previews, and contain no network calls or subprocesses. Python with Pillow and jq must be on your machine. github.com

Security advisories

In their words