Separation of Concerns: Engineering for Vibe Coders
One of the fastest ways a prototype becomes fragile is when everything is mixed together. UI logic talks directly to databases. AI prompts live next to HTTP handlers. Business rules are scattered everywhere. This happens often in vibe coding because the goal is speed, not structure.
Separation of concerns is the practice of organizing your system so that each part has a clear responsibility. It does not slow you down. It actually makes prototypes easier to change, debug, and evolve.
Planning separation early helps your prototype grow without collapsing under its own complexity.
1. What separation of concerns means
Separation of concerns means dividing your application into parts, where each part focuses on a single responsibility.
Examples:
- UI handles user interaction, not data storage
- Business logic makes decisions, not HTTP calls
- Data access talks to databases, not the AI model
- AI orchestration is separate from request handling
Each concern can change independently without breaking everything else.
🟢 Pre-prototype habit:
Before coding, list the major responsibilities in your app. Write one sentence for what each part should do and what it should not do.
2. Why separation matters for vibe coders
Vibe coding often starts with a single file or script. That works until:
- You need to change one feature and break three others
- Debugging becomes guessing
- Adding a new AI model requires rewriting everything
- You cannot explain how your app works anymore
Separation of concerns gives you:
- Clear mental models
- Safer changes
- Faster debugging
- Easier collaboration or handoff later
🟢 Pre-prototype habit:
Ask yourself: “If I change this one thing, what else should not need to change?” Use that answer to define boundaries.
3. Common concerns to separate in AI prototypes
Even small AI prototypes usually benefit from separating:
- Input handling (HTTP, UI, CLI)
- Business logic (rules, decisions, workflows)
- AI logic (prompting, inference, retries)
- Data access (databases, files, external APIs)
- Infrastructure concerns (logging, config, auth)
You do not need many files or services. You just need clear boundaries.
🟢 Pre-prototype habit:
Sketch a simple box diagram showing these concerns. Draw arrows only where communication is truly needed.
4. What separation is not
Separation of concerns does not mean:
- Overengineering
- Dozens of microservices
- Complex frameworks
- Abstracting everything too early
It means intentional grouping and clear ownership. Even one file can respect separation if responsibilities are clearly defined.
🟢 Pre-prototype habit:
Decide what level of separation is “good enough” for this prototype. Aim for clarity, not perfection.
5. How separation supports future growth
Prototypes often become real products. When concerns are separated:
- You can swap AI models without touching UI code
- You can add caching without changing business logic
- You can scale infrastructure without rewriting workflows
- You can test pieces independently
Separation keeps your future options open.
🟢 Pre-prototype habit:
Identify which parts of your prototype are most likely to change. Make sure they are isolated from the rest.
6. Quick pre-prototype checklist
| Checklist Item | Why It Matters |
|---|---|
| List core responsibilities | Prevents tangled logic |
| Define what each part should not do | Clarifies boundaries |
| Separate AI, business, and data logic | Enables safe iteration |
| Sketch boundaries before coding | Reduces refactors later |
| Keep separation lightweight | Avoids overengineering |
Closing note
Separation of concerns is one of the most powerful habits a vibe coder can adopt. It makes prototypes easier to reason about, safer to change, and far more likely to survive real-world use.
🟢 Pre-prototype habit:
Before writing code, define responsibilities, draw simple boundaries, and commit to keeping concerns separate. A little structure early saves massive effort later.
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