Vibe coding is how juniors ship bugs fast.
You describe a feature in natural language, the AI generates code,
you tweak until it works. Fast? Yes. Scalable? No.
At scale, vibe coding gives you:
- 500 lines of unreviewable code
- Features you didn't ask for
- An agent that rewrites half your codebase
The fix: Spec-Driven Development
Senior engineers don't prompt AI directly. They write specs first.
Three documents you need:
1. PRD (Product Requirements Doc) — what you're building and why
2. Technical Design Doc — architecture, data models, API contracts
3. AI Spec — precise instructions for the agent, edge cases included
The agent works from the spec. Not from vibes.
Example: JWT Authentication
Instead of prompting "add JWT auth", you write a spec that defines:
- Token structure and expiry
- Refresh logic
- Error handling for each case
- What the agent should NOT touch
Result: reviewable, production-grade code.
The 5-step workflow
- Write PRD
- Write Technical Design Doc
- Generate AI Spec from the two above
- Run agent against the spec
- Review diff — not the entire codebase
Full breakdown with examples in the video:
https://youtu.be/5ve3_inIN-8
