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

<p><strong><a href="https://simonw.github.io/raccoon-heist-codex/">Moonlight &amp; Mayhem (Raccoon Heist by Codex + GPT-5.6 Sol Ultra)</a></strong></p> On Wednesday I wrote about <a href="https://simonwillison.net/2026/Aug/5/raccoon-heist/">One-shotting a Raccoon Heist game using Claude Fable 5</a>, where I had Claude Fable 5 build a full working game from a premise I generated with GPT-3 and DALL-E <a href="https://twitter.com/simonw/status/1555626060384911360">four years ago</a>.</p> <p>I decided to pose the exact same prompt to Codex Desktop running GPT-5.6 Sol Ultra - the mode where Sol makes <em>aggressive</em> use of sub-agents - to see how it would do.</p> <p>It produced a much better game! Here's <a href="https://simonw.github.io/raccoon-heist-codex/">Moonlight &amp; Mayhem</a> - <a href="https://github.com/simonw/raccoon-heist-codex/">GitHub repository here</a>, including the <a href="https://github.com/simonw/raccoon-heist-codex/tree/main/output/imagegen">textures and prompts</a> it generated using <code>gpt-image-2</code>.</p> <p><video controls="controls" preload="none" poster="https://static.simonwillison.net/static/2026/raccoon-heist-codex-poster.jpg" width="1280" height="720" style="display: block; width: 100%; height: auto;" > <source src="https://static.simonwillison.net/static/2026/raccoon-heist-codex-720p.mp4" type="video/mp4" /> Your browser does not support HTML5 video. </video> </p> <p>The original GPT-3 generated game description included:</p> <blockquote> <p>In “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.</p> </blockquote> <p>Fable'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.</p> <p>Much more heisty!</p> <p>There 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!</p> <p><img alt="The main player character racoon is visible with an enormous polygon-based black sphere four times the size of its body overlapping its head, with a white pupil on it." src="https://static.simonwillison.net/static/2026/raccoon-heist-codex-bug.jpg" /></p> <p>You can <a href="https://static.simonwillison.net/static/2026/raccoon-heist-eyeball-edition/">play that version here</a>.</p> <p>Despite reviewing screenshots during development Codex failed to spot and correct this bug.</p> <p>I fixed it by prompting:</p> <blockquote> <p>Why do the raccoons have huge black spheres on them?</p> </blockquote> <p>And then:</p> <blockquote> <p>Fix it</p> </blockquote> <p>Which resulted in <a href="https://github.com/simonw/raccoon-heist-codex/commit/4e9a390dfbe80533324ee61a37aa661813c08446">this fix</a>.</p> <p>I shared <a href="https://github.com/simonw/raccoon-heist-codex/blob/main/transcript.md">the full Codex transcript</a> in the repository - I wish Claude Code had the same "copy as Markdown" feature. <p>Tags: <a href="https://simonwillison.net/tags/game-design">game-design</a>, <a href="https://simonwillison.net/tags/ai">ai</a>, <a href="https://simonwillison.net/tags/openai">openai</a>, <a href="https://simonwillison.net/tags/generative-ai">generative-ai</a>, <a href="https://simonwillison.net/tags/llms">llms</a>, <a href="https://simonwillison.net/tags/coding-agents">coding-agents</a>, <a href="https://simonwillison.net/tags/gpt">gpt</a></p>