Thinking on product truth, behavior specs, and building software teams can reason about.
Subscribe via RSSA step-by-step guide to writing a .pbc.md file for your product's most critical module. Start with plain Markdown; add structured blocks agents can read.
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.
AI agents have AGENTS.md, memory banks, harnesses, and monitors. They still lack the product context layer — what the product promises and what must hold.
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.
Your repo has workflow instructions, session context, and feature specs. None of them answer what the product promises to do. That's the PBC layer.