Mr Z
Is Mr Z Built on ChatGPT or Claude?
Francesco Zen, founder of ZTraining · Last updated June 19, 2026
What "built on Claude" actually means here
Claude is the model powering the conversation itself. What makes Mr Z what it is sits on top of that: Francesco's own way of coaching, his persona, and the specific formulas and systems developed across 18 years of real client work. The model provides the engine. The method provides everything that actually matters in the advice itself.
Why this distinction matters
Plenty of AI tools are a generic model with a fitness-themed prompt attached. Mr Z is the reverse: a specific, tested coaching method, encoded into an AI built to deliver it consistently, at scale, to far more people than one coach could ever reach alone.
Related: Why I built an AI version of my coaching method · An AI coach in your browser, why and how
