When I first heard about vibe coding, the promise was simple: describe what you want, and AI builds it. No coding required. People were building apps in hours.
The promise was real. But it only works for specific use cases.
What Is Vibe Coding?
Vibe coding is AI-assisted development using natural language. You describe your goal. AI generates the code.
The umbrella term covers two very different approaches: pure vibe coding and spec-driven development.
Pure Vibe Coding: Speed Without Structure
AI researcher Andrej Karpathy coined the term and described the purest form: “Fully give in to the vibes, embrace exponentials, and forget that the code even exists.”
You describe what you want. AI generates code. You test if it works. You deploy without necessarily understanding the implementation.
This works when:
- You need UI mockups quickly
- You’re prototyping to validate an idea
- The scope is small and well-defined
- You’re building something temporary
Where it breaks down:
I burned through $20 in API credits trying to get Claude to fix an error it created in its own code. I’d implement feature A, add feature B, and feature A would break. Fix A, add feature C, and feature B would break.
That’s the loop of death. When previously working features keep breaking as you add new ones, complexity has caught up with you.
The root cause: I wasn’t providing enough detail up front because I didn’t fully know what I wanted. The AI didn’t have context to architect things well. I couldn’t guide it effectively because I didn’t understand how the code worked.
Spec-Driven Development: Structure Enables Speed
Spec-driven development adds discipline before, during, and after code generation.
The process:
Specify — I describe high-level vision and main functionality. AI asks follow-up questions to drill down into edge cases, additional options, and aspects I haven’t considered. This refines the idea before any code gets written.
Plan — AI decomposes the spec into a task list with implementation steps: function definitions, code snippets, file structures. I provide direction and answer questions.
Execute — AI writes code with clear guidance from the spec and tasks.
Verify — Review every file. Build a mental model of how the app works. Test manually.
Document — Commit and move to the next spec. AI helps capture decisions and learnings.
This takes longer up front. But the code works and keeps working.
The Key Difference: Mutual Understanding
The breakthrough is mutual understanding between you and the AI.
You’re forced to think through requirements, which informs implementation. The AI can plot out a better architecture and anticipate edge cases.
When you provide context up front, the AI builds better code. When you review the code, you can steer it effectively.
Spec-Driven Development Makes Vibe Coding Reliable
I built ChromaCal, a color-coded calendar app, multiple times using different approaches. The version that finally worked was built in Replit in a couple hours.
But I’d already done the hard spec-driven planning work in Claude Code first. When I gave Replit that detailed spec as the initial prompt, it built all the business logic almost perfectly.
This is the key insight: spec-driven planning creates the clarity that makes pure vibe coding work.
You can layer spec-driven development onto any vibe coding tool. The structured planning process makes the vibe coding execution dramatically more effective. They’re not competing approaches. Spec-driven development is what makes vibe coding viable for serious work.
When to Use Each
| Aspect | Pure Vibe Coding | Spec-Driven Development |
|---|---|---|
| Speed | Very fast initially | Faster long-term |
| Code Review | Minimal | Comprehensive |
| Understanding | Optional (small scope) | Required |
| Maintainability | Low | High |
| Extensibility | Breaks easily | Built for change |
| Security | Limited | Robust |
| Production Ready | Limited use cases only | Yes |
Use pure vibe coding for UI mockups, quick prototypes, and throwaway experiments.
Use spec-driven development for production apps, complex systems, and code you’ll maintain.
The line is simple: will someone rely on this code next month?
Getting Started
For spec-driven development in Claude Code, I use AgentOS. It’s a structured framework that prompts the AI to do research, validation, and enumeration before building.
For quick UI mockups, I use Claude on the web or Replit. Pure vibe coding excels there.
The core principle: Use AI for speed. Maintain engineering discipline for quality.
Want implementation details? I’ll be publishing a complete guide to Spec-Driven Development with step-by-step workflows soon.
Ready to try spec-driven development now? Check out AgentOS for a structured workflow in Claude Code.