Kylon Bloom, a Codex Pet You Can Download

We turned the Kylon mascot into a Codex pet. It is called Kylon Bloom, and it sits in the corner of your screen telling you whether Codex is working, stuck, or waiting on you. It is free.

Nine states

• Idle: breathes quietly, blinks now and then
• Running right / running left: a side-profile walk cycle
• Waving: greets you when you come back
• Jumping: crouches, launches, tucks at the peak, lands
• Failed: head drops and a single tear falls
• Waiting: tilts its head and holds a palm up, asking
• Running: folds its arms in front and concentrates
• Review: hand under the chin, eyes narrowed

Download

Download kylon-bloom-codex-pet.zip (about 800KB). Inside are two files, pet.json and spritesheet.webp. The spritesheet on its own is there too.

Install

1. Let Codex do it

You do not have to download or unzip anything yourself. Paste this into the Codex composer:

Download https://kylon.io/pets/kylon-bloom/kylon-bloom-codex-pet.zip and unpack it into ~/.codex/pets/kylon/ so that pet.json and spritesheet.webp sit directly in that folder. Confirm both files are there when you are done.

If you would rather do it by hand, unzip the download into the same place:

mkdir -p ~/.codex/pets/kylon
cd ~/.codex/pets/kylon
unzip ~/Downloads/kylon-bloom-codex-pet.zip

2. Restart the Codex app

A running app will not pick up a new pet. Quit it and open it again.

3. Pick it under Settings, Appearance, Pets

Kylon appears in the list. Typing /pet in the composer toggles the overlay on and off.

What Codex pets are

Optional animated companions OpenAI added to the Codex app in May 2026. They write no code. They sit in a floating overlay and show whether the active thread is running, waiting for input, or ready for review (Engadget, 2 May 2026). Alongside the built-in options you can add your own, and the community gallery has passed 3,000 published pets (Codex Pets).

Also worth a look: connecting Codex to a Kylon workspace and Codex and Claude Code, agents at home.