Vibe code is code you don't understand.  

(via) Steve Krouse nails the difference between vibe coding and programming with AI assistance: “Vibe coding is on a spectrum of how much you understand the code. The more you understand, the less you are vibing.”

His graph is a useful check to plot your own AI-assisted coding projects. Rapid prototypes, hobby apps, and low-stakes, low-maintenance projects are great candidates to be high on vibes, while the serious stuff you intend to expand and maintain should land further on understanding.