Vibe Coding for Product Managers: Stop Writing, Start Building
The most successful startup I’ve worked with shipped their MVP in 6 weeks.
The least successful one spent 4 months writing specs for a product that never launched.
Here’s what I’ve learned after helping dozens of teams transition from traditional planning to AI-powered development: writing-first culture made sense when building was expensive and slow. Now it’s just bureaucracy.
The Old Rules Don’t Apply
Traditional product development assumed a simple truth—building costs more than planning. You had to get the requirements right because changing code later meant weeks of developer time. So we created elaborate rituals: PRDs, wireframes, stakeholder reviews, more PRDs.
But AI has flipped the economics. I can prototype a feature in an afternoon that would have taken a week to build just two years ago. The cost of building is approaching the cost of writing about building.
When that happens, the smart move is obvious: build first, document what works.
The Demo + One-Pager Method
Here’s what actually works. Instead of starting with a 20-page PRD, start with a demo and a single page that covers:
- The problem you’re solving
- What the prototype proves (and what it doesn’t)
- The success metric you hit
Show, don’t tell. Let the working prototype carry the story while the one-pager handles the contracts and commitments.
When Writing Still Wins
Build-first doesn’t mean write-never. Some decisions are too expensive to prototype:
- Cross-team dependencies spanning quarters need written agreements.
- Data that leaves your system needs compliance review.
- Changes to shared schemas or billing flows need careful coordination.
These represent maybe 20% of your product decisions. The other 80%—the user flows, interaction patterns, and feature discovery—can be prototyped faster than they can be specified.
The Future Belongs to Builders
As AI tools get better, the gap between thinking and building will continue to shrink. Teams that master build-first culture now will have a massive advantage when prototyping becomes as fast as thinking.
The companies still writing elaborate specs while their competitors are shipping will find themselves in the same position as those who insisted on fax machines when email became ubiquitous.
Your choice: evolve your process to match your new capabilities, or watch faster teams eat your market while you’re still planning what to build.
P.S. AI makes mistakes. I'm fixing that and making AI smarter. Loved by engineers from Google, Uber, and more. Check out Giga AI.
