{"slug": "moonlight-mayhem-raccoon-heist-by-codex-gpt-5-6-sol-ultra", "title": "Moonlight & Mayhem (Raccoon Heist by Codex + GPT-5.6 Sol Ultra)", "summary": "Simon Willison used OpenAI's Codex Desktop running GPT-5.6 Sol Ultra to generate a raccoon-themed heist game called Moonlight & Mayhem, which he published on GitHub. The AI-produced game improved on an earlier GPT-3 version by featuring a museum heist where the player rescues raccoon crewmates, but it initially included a bug with oversized eyeballs that Willison fixed via prompts. Codex spent 52 minutes on the project, and the session's cost was estimated at full API prices via AgentsView.", "body_md": "[Moonlight & Mayhem (Raccoon Heist by Codex + GPT-5.6 Sol Ultra)](https://simonw.github.io/raccoon-heist-codex/)\n\nI decided to pose the [exact same prompt](https://simonwillison.net/2026/Aug/5/raccoon-heist/#the-fable-5-prompt) to Codex Desktop running GPT-5.6 Sol Ultra - the mode where Sol makes *aggressive* use of sub-agents - to see how it would do.\n\nIt produced a much better game! Here's [Moonlight & Mayhem](https://simonw.github.io/raccoon-heist-codex/) - [GitHub repository here](https://github.com/simonw/raccoon-heist-codex/), including the [textures and prompts](https://github.com/simonw/raccoon-heist-codex/tree/main/output/imagegen) it generated using `gpt-image-2`\n\n.\n\nThe original GPT-3 generated game description included:\n\nIn “Raccoon Heist”, you and your team of thieving raccoons are tasked with pulling off a series of daring heists. From robbing banks to stealing priceless art, no job is too big or too small for your furry crew.\n\nFable's version had you as a single raccoon running around a back yard collecting coins and fish. GPT-5.6 Sol has you in a museum, rescuing your two other raccoon crewmates in order to stack on top of each other and bust the golden sardine out of its case.\n\nMuch more heisty!\n\nThere was one catch though: the version produced from the one-shot prompt had a bug where each raccoon had an eyeball that was enlarged to the size of a giant sphere floating over their head!\n\nYou can [play that version here](https://static.simonwillison.net/static/2026/raccoon-heist-eyeball-edition/).\n\nDespite reviewing screenshots during development Codex failed to spot and correct this bug.\n\nI fixed it by prompting:\n\n`Why do the raccoons have huge black spheres on them?`\n\nAnd then:\n\n`Fix it`\n\nWhich resulted in [this fix](https://github.com/simonw/raccoon-heist-codex/commit/4e9a390dfbe80533324ee61a37aa661813c08446).\n\nI shared [the full Codex transcript](https://github.com/simonw/raccoon-heist-codex/blob/main/transcript.md) in the repository - I wish Claude Code had the same \"copy as Markdown\" feature.\n\nCodex spent 52 minutes on the project. Here's the [AgentsView](https://www.agentsview.io) cost estimate for that session if I had been paying full API prices as opposed to using my monthly Codex subscription:\n\nTags: [game-design](https://simonwillison.net/tags/game-design), [ai](https://simonwillison.net/tags/ai), [openai](https://simonwillison.net/tags/openai), [generative-ai](https://simonwillison.net/tags/generative-ai), [llms](https://simonwillison.net/tags/llms), [coding-agents](https://simonwillison.net/tags/coding-agents), [codex](https://simonwillison.net/tags/codex), [gpt](https://simonwillison.net/tags/gpt)", "url": "https://wpnews.pro/news/moonlight-mayhem-raccoon-heist-by-codex-gpt-5-6-sol-ultra", "canonical_source": "https://simonwillison.net/2026/Aug/7/moonlight-mayhem/#atom-everything", "published_at": "2026-08-07 19:18:09+00:00", "updated_at": "2026-08-09 11:44:40.180419+00:00", "lang": "en", "topics": ["generative-ai", "ai-tools", "ai-agents"], "entities": ["Simon Willison", "OpenAI", "Codex Desktop", "GPT-5.6 Sol Ultra", "Moonlight & Mayhem", "GitHub", "AgentsView", "gpt-image-2"], "alternates": {"html": "https://wpnews.pro/news/moonlight-mayhem-raccoon-heist-by-codex-gpt-5-6-sol-ultra", "markdown": "https://wpnews.pro/news/moonlight-mayhem-raccoon-heist-by-codex-gpt-5-6-sol-ultra.md", "text": "https://wpnews.pro/news/moonlight-mayhem-raccoon-heist-by-codex-gpt-5-6-sol-ultra.txt", "jsonld": "https://wpnews.pro/news/moonlight-mayhem-raccoon-heist-by-codex-gpt-5-6-sol-ultra.jsonld"}}