I had quite a fun time getting those pelicans though... since GPT-5 Codex Mini isn't officially available via API yet I instead had OpenAI's Codex CLI tool extend itself (in Rust) to add a "codex prompt ..." tool which uses their existing custom auth scheme and backend API, then used that to generate the pelicans. Full details here: https://simonwillison.net/2025/Nov/9/gpt-5-codex-mini/
Can't believe I'm saying this, but GPT-5's pelican is its most impressive improvement over 4o I've seen. I wonder if Codex' MoE does not contain any expert fit for this task due to its fine-tuning on code.
I'll know if they do, because I'll notice that a new model is suspiciously great at drawing pelicans riding bicycles while still sucking at drawing other things.
For comparison, here's GPT-5-Codex (not mini) https://static.simonwillison.net/static/2025/codex-hacking-d... and full GPT-5: https://static.simonwillison.net/static/2025/codex-hacking-g...
I had quite a fun time getting those pelicans though... since GPT-5 Codex Mini isn't officially available via API yet I instead had OpenAI's Codex CLI tool extend itself (in Rust) to add a "codex prompt ..." tool which uses their existing custom auth scheme and backend API, then used that to generate the pelicans. Full details here: https://simonwillison.net/2025/Nov/9/gpt-5-codex-mini/