# Heat Threshold - **Event:** [Google I/O Hackathon](https://cerebralvalley.ai/e/google-io-hackathon) - **When:** Sat, May 23 at 9:00 AM – 10:00 PM (PDT) - **Where:** Shack15, San Francisco, CA - **Team:** [craig merry](https://cerebralvalley.ai/u/craigmerry) - **GitHub:** https://github.com/HeatThreshold/HeatThreshold - **Demo video:** https://youtu.be/9qWiDOWgPXs - **Gallery:** https://cerebralvalley.ai/e/google-io-hackathon/hackathon/gallery - **Page:** https://cerebralvalley.ai/e/google-io-hackathon/hackathon/gallery/25 Heat Threshold answers one question: should I go outside, and when? You type (or speak) a location, an activity, and a time. A primary Gemini 3.5 Flash agent dispatches a graph of ten sub-agents — three uploaded as persistent Managed Agent definitions, one weather cascade (NWS → Open- Meteo), and six deterministic sub-agents for routing, sun-shade math, refuge scheduling, and Street View. It returns a go / delay / alternate verdict grounded in Stull (2011) wet-bulb math and USMC 6200.1E flag thresholds. Same plan, three surfaces: a 2D bento dashboard, a playable WebXR HUD over Google Photorealistic 3D Tiles, and a Gemini Live voice mode that calls our Managed Agents pipeline as a tool — bridging the two newest Gemini APIs through function calling. Every run is traced by PlatAtlas, recorded to Vercel Blob by McpTape, and replayable via McpReplay (?replay=) — the demo safety net. Built today, 10:30 AM – 5:00 PM PT. MIT. Environmental scheduling tool, not medical advice. --- Markdown version of https://cerebralvalley.ai/e/google-io-hackathon/hackathon/gallery/25. Site index for agents: https://cerebralvalley.ai/llms.txt · full text: https://cerebralvalley.ai/llms-full.txt