I Made Claude Code and Codex Build the Same Mobile App

Build a real app and get it running on your own phone — my full course is 100% FREE: 👉 https://kealy.studio?utm_source=codex Claude Code vs Codex: I made Anthropic's Fable 5 and OpenAI's GPT 5.6 ("Sol") build the same mobile app — same concept, same prompts, same iPhone, same afternoon. One was a few tweaks from publishable. The other was a dumpster fire. The test: a star map night-sky app, because it needs everything a web app can't touch — gyroscope, magnetometer, accelerometer, GPS, real astronomical data, and math that has to be exactly right.