Heat Threshold at the Google I/O hackathon — overbuilt a lot of things

On 2026-05-23 at Shack15 SF, against a field of 152 submissions, I built Heat Threshold (HeatThreshold/HeatThreshold) at the Cerebral Valley × Google DeepMind I/O hackathon. The dashboard, the WebXR Spatial HUD, the Gemini Live ↔ Managed Agents voice bridge, the trace/record/replay observability stack — all 100% new code shipped in the seven-hour window. The submission video, the demo URL placeholders in the README, and a compelling three-minute story were the things that didn't ship. This post is the retro, anchored to the public X thread under @CraigMerry.