Claude Opus 5.5 (effort default (no --effort flag) · thinking on) on Draw a walking pixel-art character sprite animation in one self-contained HTML file

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  "result": "I wrote `out/scene.html`. I loaded it once in headless Chrome and took a screenshot after about 2 seconds of animation. The sprite and scene drew correctly, and the dump of the page contents showed no page errors. The only errors in the output were Chrome failing to connect to the system message bus (D-Bus), which is about the environment, not the page. I didn't run the actual checks: there's no browser automation library here, so I couldn't sample `sceneState()` over time or compare screenshots. The notes on each check below are how I built it.\n\n- **Self-contained:** the file is under 3 KB, with no URLs or external resources. The title is \"Pixel Walker 659\" and the stage is a 720\u00d7480 canvas, both from `spec.json`.\n- **Pixel art:** the canvas has CSS `image-rendering: pixelated` and the drawing context has `imageSmoothingEnabled = false`. The sprite is 12\u00d716 sprite pixels, each drawn as a 3\u00d73 block (`scale` 3).\n- **Walk cycle:** the frame number is computed from time since load as `floor(t\u00b74) % 6`. So it changes exactly 4 times a second, only ever steps to the next frame, wraps back to 0, and covers all 6 frames every 1.5 s. The 6 frames have different leg poses and a slight up-and-down bob.\n- **Movement:** the character walks right at 60 px/s, wraps around the stage, and starts in view. `x` is rounded to whole pixels and is the same value used to draw the sprite.\n- **State:** `window.sceneState()` returns `{frame, x, y, scale, frames, fps}`.\n- **Errors:** the drawing loop is wrapped in a try/catch, so one bad frame can't throw an uncaught exception.",
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