What they did
Imoh wanted a language tutor that taught through immersion after a 1,000-day Duolingo streak left him unable to hold a conversation in Norwegian. He wanted the app to feel native on both phones, so he had Codex build it in Swift for iOS and in Kotlin for Android, two languages he had no experience with. He framed his requests the way a product manager would, as epics and user stories tied to a specific user problem, and gave design direction in plain words, such as a minimal, Apple-quality app that should feel like autumn. The live tutoring runs on the GPT-Live real-time voice model.
How it went
Codex produced working native apps for both platforms, and Imoh showed them on Lenny Rachitsky's How I AI podcast. The first design came back in dark mode, and he steered it toward warm colours, gradients and a lighter look. When a session stalled, he started a fresh one, split the task into smaller steps and asked the agent to check its own work. No build time or build cost is given.
Worth knowing
The account comes from a podcast episode summary, so the detail is thin. The running cost is the real-time voice, not the build: Imoh puts a 30-minute tutoring session at roughly $3 to $5. He also uses a second agent to review code written by another one before accepting it.