Test a three.js game

1. Play the feature once with interact and add expect and save: interact { steps: [{ key: "Space" }], expect: { "player.y": [1.5, 3] }, save: "jump" }. expect keys are dotted paths into the state; a value is a number, string or boolean (equal), [min, max] (a range), a list of values (one of them) or null (exists). The check is written to game-tests.json in the project when every entry holds.
2. test reruns every saved check, each from a fresh reload at frame 0, one line each: ✓ jump, or ✗ jump: with the value seen and the one expected.

In Claude Code, the paprika3d plugin's after-edit hook reruns the saved checks after each edit and speaks only when one starts or stops failing. The checks read window.__game's state (the convention: ../threejs-game/SKILL.md). A Playwright suite still fits CI runs, real devices and multiplayer.

If open and test are not among your tools, the paprika3d MCP server is not installed: it runs as npx -y paprika3d serve (stdio), and https://paprika3d.com/docs/install has each agent's line.