Your vibe-coded app caught on and now people pay for it — but you can't fully explain it. Build a mental model without reading every line, top-down.
Your product works. On launch day someone asks what it does at the edges — and you'd have to open the file to answer. That gap is the real launch risk.
Vibe-coding got you a working product you can't speak for. Reclaiming it isn't slowing down — it's re-authoring what you shipped, behavior by behavior.
You own a product you can't explain — acquired, inherited, or vibe-coded with AI. Here's how to read code you didn't really write, behavior by behavior.
You vibe-coded a working product. Users use it. You can't speak for it without reading every line. The product is yours — you just don't know it yet.
Auto-extracted specs read the code, not the decisions behind it. They quietly promote placeholders and fallbacks as if settled. Sign-off is the missing step.
AI-native teams need three layers of durable memory — behavior, decisions, execution. Execution has tooling. Most teams lack the behavior layer entirely.
As engineers take on more product ownership and AI accelerates shipping, product decisions vanish into Slack and PRs. Behavior specs hold the intent.
AI makes rebuilding cheap. But product decisions are expensive to recreate from memory. Here's how a behavior spec makes 'start fresh' a feature, not a failure.
Shipping fast with AI agents feels productive. But the costliest mistake isn't bad code — it's building confidently when nobody wrote down what was decided.
PRDs capture intent. Tests verify assertions. Between them, there's no artifact tracking what the product promises — grounded in code, confirmed by humans.
When an outsourcing engagement wraps up, product knowledge walks out the door. A living behavior spec keeps it in the codebase — not in someone's head.
AI can extract product logic from your codebase. Stewie builds a living behavior spec your whole team can read — no code, no docs, no waiting on engineers.
Product owners confirm behaviors. BAs clarify logic. QA knows what to protect. New hires onboard fast. Vendors skip reverse-engineering. One shared contract.
Leaders shouldn't need three meetings to verify whether a product decision was implemented correctly. A living behavior spec is the direct line.
Your coding agent ships correct-looking code that breaks product promises. The fix isn't capability — it's the product context layer agents lack.
Shipping fast with AI coding tools is genuinely good. The problem isn't the speed — it's what gets left behind. Product reasoning doesn't survive the vibe.
A field guide to the .pbc.md format — the structured blocks that make up a Product Behavior Contract: behaviors, triggers, outcomes, and provenance.
Product knowledge lives in heads, not docs. Here's why that gap compounds — and what a behavior spec does about it.
