The key implementation details behind Codex pet creation are open source, specifically the hatch-pet skill (openai/skills) and the imagegen skill (openai/codex), both under the Apache 2.0 license.

Willison notes that the two skills powering the pet-creation feature, hatch-pet and imagegen, are open source under Apache 2.0, letting him dig into how the mechanism actually works. ✦ AI generated

Simon Willison · Simon Willison's Weblog · 2026-07-14 · original ↗

The key implementation details are open source - these two skills in particular, both Apache 2.0 licensed: hatch-pet from openai/skills, imagegen from openai/codex

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