# Sean Chang
> Research Engineer, Google Research · Health AI. Bringing better health answers to everyone.

I build the models, safety systems and infrastructure behind health answers at Google. On the side, I'm building Corneo, a skincare routine app.

## Core skills
- Health AI safety: Classifiers and evaluations that decide when a medical question or answer needs extra care.
- LLM systems and agents: Retrieval that grounds answers in search and literature, and memory that lets agents hand off context.
- Model training and research: Fine-tuning and controlled experiments, from hypothesis to a measured result.
- Cloud infrastructure at scale: Production services on GCP and AWS that stay up when real traffic arrives.
- Products, end to end: Taking an idea to a shipped app on my own: mobile, web and the backend behind them.
- Languages: Python, C++, Java, TypeScript, SQL

## Work at Google (public)
- [AI Mode in Google Search](https://blog.google/products/search/ai-mode-search/) (2025): I built the query and response classifiers that keep answers about medication dosage safe.
- [Fitbit Plan for Care](https://support.google.com/fitbit/answer/14566053?hl=en) (2025): I built its infrastructure and the conversational memory its agents share.
- [Med-Gemini](https://research.google/blog/advancing-medical-ai-with-med-gemini/) (2024): I studied answers written for consumers, grounded in fast Google Search and medical literature through a retrieval (RAG) harness.

## Side project
- [Corneo](https://corneo.app): Builds a routine from the products you already own, then adjusts it as your skin changes. Recommendations lean on evidence, not hype.

## Links
- LinkedIn: https://www.linkedin.com/in/seantc/

## Machine access
- MCP (Streamable HTTP): https://seanchang.me/mcp
- Latest updates (JSON): https://seanchang.me/api/now
- Updates feed (RSS): https://seanchang.me/feed.xml