Anthropic PMs don't write PRDs. They use Claude Code to build the first version of the feature themselves. The whole company dogfoods it for weeks. Then they ship an experiment. Anthropic went from $1B run-rate revenue at the start of 2025 to over $9B by year end. Claude Code alone generates over $500M in run-rate revenue with usage growing 10x in three months. The company signed a term sheet at $350B, nearly doubling from $183B just months earlier. This is what happens when you eliminate handoff drift. In a traditional org, a PM writes a spec. Design interprets the spec. Engineering interprets the design. Each handoff introduces drift. Each handoff adds a week. The 2-4 week cycle of PRD → design → ticket → sprint → build → QA compresses to days when the PM can prototype in the codebase. The prerequisite is making your codebase AI-friendly. Tailwind instead of scattered CSS files. Microservices architecture. Reduced codebase size. That infrastructure investment is what lets PMs vibe code directly against production components. The math is simple. If your experimentation cycle is 8 weeks per test and your competitor's cycle is 3 days, they're running 13x more experiments per quarter. Compound that over a year and the learning gap becomes insurmountable. Walked through the full Claude Code project structure, skills setup, and how to get from zero to shipping in the talk.