Pit three agents against a browser shooter build
Three coding agents independently built the same multiplayer shooter, letting the team compare their strengths and weak spots.
- What they did
- InstantDB had Codex Max 5.1, Opus 4.5, and Gemini 3 Pro each work on a multiplayer browser shooter through their own provider CLI, with default settings and a top-tier plan. They were each fed roughly seven prompts: the opening four asked for a local three.js game with a map, opponents, a gun, and audio, while the last three added Instant presence and topics plus a map catalog stored in a database. When errors appeared, the people running the test usually sent the messages back into the agents.
- How it went
- In the end, all three produced a playable 3D multiplayer shooter without any hand-written code. Opus delivered the strongest frontend, Gemini did best on the backend, and Codex came somewhere in the middle. Opus also got bogged down by React useEffect issues until engineers inspected its code.
- Tips
- Plan to bounce build and runtime errors back into the agent, since that was part of the workflow. If one gets stuck, open the code yourself and check the logic instead of waiting for it to recover.
Try it yourself with Codex
Create a browser game in the style of [game] using [stack]. Start with a local prototype that includes [movement], [shooting], [health], [enemy behavior], [sound], and [map]. After that, add multiplayer for [number] players in one shared room using [realtime backend] with presence and room updates, then finish with a map list stored in the database. Pause before any step that would delete data, send data out, or make a payment, and ask me to approve it first. If you run into an error, tell me exactly what to paste back and wait for that text before moving on. When you think the project is complete, give me a short list of what works and what still needs attention.
Fill in the [brackets]. Agents can make mistakes, so review anything before it is sent, paid or deleted.
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