# Takafumi Mizuguchi

- **Event:** [Built with Opus 4.7: a Claude Code hackathon](https://cerebralvalley.ai/e/built-with-4-7-hackathon)
- **When:** Apr 21 at 12:00 PM – Apr 27 at 2:00 AM (EDT)
- **Where:** Online
- **Team:** [Takafumi Mizuguchi](https://cerebralvalley.ai/u/guttyo)
- **GitHub:** https://github.com/Guttyo/yorukusu
- **Demo video:** https://youtu.be/FdMz9ZeP1Dg
- **Gallery:** https://cerebralvalley.ai/e/built-with-4-7-hackathon/hackathon/gallery
- **Page:** https://cerebralvalley.ai/e/built-with-4-7-hackathon/hackathon/gallery/107

At 2 AM a parent's child has a fever. Three options: call a professional, drive to an open pharmacy, or wait until morning. The right one needs medical judgment the parent doesn't have. Japan's pediatric advice line takes 1.24M such calls a year — and its own ministry flags eleven structural gaps.

Yorukusu is a SwiftUI iOS app that loads a pharmacist-authored Agent Skill (red-flag screening, OTC-only logic, parent-facing safety rationale), reconciles against a device-local Personal Health Context, and asks Claude Opus 4.7 to return one of three answers: CALL the right emergency number, GO to a pharmacy with a pharmacist on duty, or WAIT with explicit warning signs. Yorukusu does not diagnose — pharmacist-informed, not pharmacist-replacing.

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