Moonlight & Mayhem (Raccoon Heist by Codex + GPT-5.6 Sol Ultra)

Simon Willison tested GPT-5.6 Sol Ultra against Claude Fable 5 using identical prompts to build a Raccoon Heist game. Sol Ultra produced a more ambitious version where you rescue and stack your raccoon teammates to steal a golden sardine from a museum. Fable's version was simpler — a single raccoon collecting coins and fish. Both games started from a game concept GPT-3 had generated four years earlier. Sol Ultra's version had one significant flaw: the raccoons had enormous black eyeballs floating above their heads. Despite reviewing screenshots during development, the AI didn't spot or fix the bug itself. Willison corrected it with targeted follow-up prompts, illustrating that sophisticated coding agents still benefit from human review.

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