Arunraj Rajendran says AI is replacing PRDs with PM-built prototypes

Arunraj Rajendran, writing on LinkedIn, argues that AI is displacing the product requirements document as the PM's default output, replacing it with working prototypes built before engineering planning even starts. His case rests on contrast rather than evidence: a PRD can describe a workflow, he writes, but only a prototype reveals whether it makes sense or where users hesitate. He frames this as a shift in what PMs do, from describing experiences to simulating them, from abstract alignment to concrete reaction. The post offers no examples, teams, or outcomes to back the claim, just an assertion that product thinking is becoming more executable and that PMs are increasingly becoming builders.