Yamakei.info

Notes on building reliable software with AI in the loop.

Case Studies

Flagship Case Study

Moyai System

flagship

Designing a privacy-first, want-driven coordination system using AI-assisted full-stack development.

Duration: ~1 weekDate: 2026-01-21

Tools: Next.js, Supabase, PostgreSQL, Row Level Security, pgvector, OpenAI APIs, ChatGPT, Cursor, GitHub Copilot

RallyHub MVP

flagship

Validating AI-assisted full-stack mobile development through a solo-built, production-ready MVP.

Duration: 10 daysDate: 2025-12-20

Tools: React Native, Expo, Supabase, Postgres, ChatGPT, Cursor, GitHub Copilot

How AI compressed implementation time and exposed design clarity as the true bottleneck.

Duration: 7-8 days (over 3 weeks)Date: 2026-01-09

Tools: React, Next.js, Expo, Supabase, Postgres, ChatGPT, Cursor, Claude Code, Codex