simonw/pedalican

Simon Willison · Simon Willison · 2026-07-14

Simon Willison created a custom animated pelican-on-bicycle Codex Desktop companion called Pedalican, using GPT-5.6 Sol and gpt-image-2 to generate game-ready sprite assets from text prompts, and documents the open-source implementation.

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Appears in

AI-Assisted Coding Culture: Landmark Rewrites, PR Description Backlash, and Prompting Debates

Extraction

Topics: generative-aitext-to-imagecodex-desktopsprite-generationai-assisted-development

Claims

OpenAI's Codex Desktop supports customizable animated pet companions that users can create through natural language prompts.
GPT-5.6 Sol used gpt-image-2 across multiple generation rounds to produce sprite assets for the custom pet.
The pet creation pipeline is open source under Apache 2.0 via the hatch-pet and imagegen skills in the openai/skills and openai/codex repositories.
The sprite generation process uses chroma-key magenta backgrounds to enable animation compositing.

Key quotes

I told it I wanted a custom pet that was a pelican riding a bicycle and GPT-5.6 Sol xhigh did the rest of the work, using several rounds with gpt-image-2 to generate the necessary sprite assets.

I've been looking out for ways to use image generation to create simple game-ready sprites, so I spent some time digging into this mechanism to see how it works.