Arize's CPO said code is so cheap now that product taste is the only alpha left. Then she proved it live by building a PM agent in one prompt. She raised $131M building the observability platform Uber, DoorDash, and the top AI teams use to debug their agents. She knows what separates the best AI PMs from the rest. Her answer: the ability to define what "good" looks like, at scale, faster than anyone else on the team. She opened Claude Code with an empty directory. One prompt: build a PM agent…