Games / AI games / Made with Opus

A game made with Claude Opus

Before Fable 5, there was the long middle of the project: hundreds of Claude Code sessions with Opus-class models that turned "what if a card MOBA lived in a browser tab" into a live game with ranked ladders and people who get mad at their duo partner. This page is about that workflow.

The shape of the work

Opus built Plops the way a good senior engineer builds: in vertical slices that each leave the game shippable. The 20Hz server simulation and its client prediction. The procedural canvas art system — every unit in the game is a draw function, zero image assets, which means "new card" is a code review, not an art pipeline. Matchmaking with duo queues. Touch controls that survive real phones. Each one started as a paragraph of intent and ended as a tested diff plus a changelog line for the deploy log.

Three habits that made it work

• The server is the referee, always. We set the invariant once — nothing the client computes is trusted — and held every session to it. Model-written code is fast to produce, so architecture rules matter more, not less: they're what keeps velocity from becoming sprawl.
• Typecheck is the handshake. No session ends without npm run typecheck passing. It sounds small; it's the difference between "the model helped" and "the model contributed to main."
• Play every build. A model can't feel that a dash is 80ms too floaty. The human plays, describes the wrongness in words ("it turns like a shopping cart"), and the model translates the complaint into physics constants. That loop, repeated a thousand times, is where game feel comes from.

What surprised us

The comedy survived. A game where fruit fights fried food needs jokes in its bones — card names, death animations, the way a tomato hero glares. We expected AI sessions to flatten the voice; instead the models turned out to be good comic collaborators once the tone was established, and ruthless about consistency in a way tired humans aren't. The style guide lives in the codebase itself, and every session reads it before touching anything — the same discipline we use for the tools we share on Forge.

Where it goes from here

The same workflow is now building Toots (a 64-player wind-powered arena) and Paintball, with the newest models doing in a session what used to take a week — that story is at made with Fable 5. The proof, as always, is playable: plops.io, free, in your browser, right now.