Four students building AI that knows when to care.

We're Meterstone Studio, a student team in California. Our first project is Brooo, an AI companion for teens.

  1. LeoData & decision systems
  2. ZerlinaDesign & user experience
  3. RyanHealth & behavioral science
  4. RoyAI & software engineering

Young minds. Bold ideas. Real impact.

  • Leo

    Data & decision systems

    Data analysis, decision-making models, and evaluating how well the product works, so Brooo is built on evidence.

    Future direction: mathematics, computer science, management information systems

  • Zerlina

    Design & user experience

    User interfaces, interactive experiences and visual design that make Brooo intuitive and engaging.

    Future direction: game design, wearable and interaction design

  • Ryan

    Health & behavioral science

    Project planning, health research, and bringing scientific findings into Brooo's development.

    Future direction: sports medicine, health science

  • Roy

    AI & software engineering

    App development, AI features and system integration: Brooo's technical foundation.

    Future direction: computer science, AI

From a family health app to a friend for teens.

We started in the summer of 2026 with Re-Balance Health, a family health web app. Brooo grew out of it, built around one idea: an app that notices how you're doing, and says something first.

Brooo reads a short daily summary from Apple Health and decides, each time, whether a message would help right now or whether it should stay quiet. When it does reach out, it sounds like a friend, not a dashboard.

  1. We start with Re-Balance Health, a family health web app.

  2. Brooo's public beta opens on TestFlight, with chat, Apple Health check-ins and Discord.

  3. ReachOut-Bench goes public: 1,003 test moments, with open code and data.

  4. Brooo moves to a painted planet, with voice mode and an island to visit.

  5. Meterstone Studio gets its logo, and this website.

Technology that checks in should know when not to.

  • Check in first, but know when to stay quiet.

    A message at the wrong moment is just noise. We grade every version of Brooo on when it reaches out, not only on what it says.

  • Raw health data stays on the phone.

    Brooo works from a short daily summary, and only after you agree to share it.

  • Show our work.

    ReachOut-Bench, the test we built, is public: the code, the data and the scores.

  • Feel like a friend, not a dashboard.

    Brooo lives on a painted planet, talks in subtitles, and keeps a shelf of keepsakes from your check-ins.

Project advisor

Junwei Wu, Emory University

Built with

Swift, SwiftUI, HealthKit, ActivityKit and Metal on the iPhone. JavaScript, Node.js, LangChain and SQLite on the server.

Our first project is Brooo.

An AI companion for teens that knows when to reach out, and when to stay quiet.

Meet Brooo Our research