Build a racing game from a single prompt
From the linked report, codex got one detailed prompt for a Three.js voxel kart racer, plus an image generation skill and a web game development skill. It then worked alone, acting as designer, developer and QA tester by playing the game. The build produced a racing game with different racers, eight maps and space-bar items, powered by over 7 million tokens.
- Agent or tool
- Codex
- Topic
- Productivity
- Reported on
- GitHub
- Added
- 2026-10-15
Why it matters
Small, repetitive tasks eat more of the week than anyone likes to admit. Cases like this show an agent taking a chore off someone's plate end to end, not just suggesting what to do. It is one of 196 sightings filed under Productivity on Agent Sightings (number 168 by interest), and one of 32 involving Codex.
How you could try it
Here is a reusable prompt, written by us in our own words, that captures the task. Paste it into Codex or any similar agent and adjust the details to your situation.
Help me build a racing game from a single prompt. Break it into steps, show your work, and wait for confirmation before anything irreversible, paid, or outbound.
Tip: Start small: run it once on a low-stakes example, read what the agent did, and only then let it run on real work.
Source
Read the original first-hand account on GitHub: https://github.com/marco-scpo/codexgame. Our summary is a paraphrase; details are in the source.