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Vibe Coding vs Hand Coding: Why AI-Built Code Turns Into Rework

· 5 min read
Codalio Team
Codalio Team
AI app builder team

Why does vibe-coded software turn into rework?​

Vibe-coded software turns into rework because the code arrives before the decisions do. AI tools can generate a working screen in minutes, but nobody wrote down the business rules, edge cases or data the product depends on. When those gaps show up later, the founder rebuilds. Going back to hand coding doesn't fix that. Writing a spec does.

That argument sits underneath one of the most argued recent Hacker News threads on AI-assisted development. In an essay on autodidacts.io, a developer said writing code by hand is more satisfying than vibe coding. They compared vibe coding to running a company that is barely under your control. The thread drew more comments than upvotes, which shows how sore a spot this is.

Developers are arguing about craft. Non-technical founders should read the same debate as a preview of their own rebuild.

If you can't explain what your software should do, AI will decide for you, and you'll find out what it chose from your customers.

Why vibe coding ships prototypes but not products​

Vibe coding is genuinely good at one thing: making an idea visible. You describe an app, the tool produces something clickable, and for the first time your pitch has a screen. For a demo or an early conversation with users, that has real value.

The trouble starts when the prototype gets promoted to product. The prompt that built it was a vibe: a few sentences of intent. The model guessed everything the prompt left out. Who can see which records? What happens when a payment fails halfway through? Which fields are required, and what should the system do when a user does something nobody planned for?

Every guess turns into code. And since nobody made those calls on purpose, nobody can tell which guesses are wrong until a customer runs into one.

The rework isn't caused by AI writing bad code. It's caused by AI writing code for decisions nobody made.

The developer in that essay was describing this from the inside: code you didn't write and don't fully understand, doing things you never chose. A developer can at least read it. A non-technical founder can't, so they lose control completely, and it tends to surface at the worst time. That might be right after launch, right before a fundraise, or when the first technical hire opens the repo and recommends starting over.

Is hand coding the answer? Not for founders.​

The Hacker News instinct is to go back to the keyboard. For an experienced engineer, that can be a reasonable call. For a non-technical founder it isn't an option, and it gets the problem wrong anyway.

Hand coding doesn't prevent rework. Clarity does.

Engineers who write every line by hand still rebuild when the requirements were vague. They've just paid that cost slowly, through sprints and refactors. What matters isn't who types the code. What matters is whether the product was specified before anyone typed anything.

That's the middle path the vibe-vs-hand debate leaves out, and it's at the center of how Codalio sees this: vibe coding ships prototypes, and spec-driven development ships products. A spec turns guesses into decisions, and AI can only build reliably on decisions.

A useful spec doesn't have to be a binder. It has to answer a handful of questions clearly:

  • Who the users are and what each role is allowed to do

  • The core workflows, step by step, including what happens when something fails

  • The data the product stores and how records relate to each other

  • The business rules: pricing logic, approvals, limits, notifications

  • What is explicitly out of scope for v1

This is where the tools differ. Lovable and Replit are fast at turning a prompt into a running app, which helps when you're exploring an idea. Cursor makes developers who already know what they're building much faster. In each case you start from a prompt or an existing codebase, not a spec you've reviewed. Codalio starts from the spec. Its workflow runs from idea to PRD to working prototype, so the code is generated from business logic you've signed off on rather than guessed from a paragraph. That is why the output holds up in production instead of heading for a rebuild.

What should a founder do before building an MVP?​

You don't need to pick a side in the vibe-vs-hand argument. You need to do the part both sides skip. Here's where to start this week:

  • Write the spec before the prompt. One page per core workflow is enough. If you can't describe what happens when a payment fails, the AI can't either.

  • Treat the prototype as a prototype. If you've already vibe-coded something, keep it. Use it to test whether people want the product, not as the foundation you'll scale.

  • Review decisions, not code. You can't audit a codebase, but you can audit a spec. For every rule, ask whether it matches how your business actually works.

  • Scope v1 hard. Every feature you cut is a set of edge cases you don't have to specify, build or fix.

Speed was never the problem. The problem is building fast on top of questions nobody answered. Make those decisions first, and AI speed starts working for you instead of against you.

Codalio is the only AI platform that takes non-technical founders from idea to PRD to working prototype — without the rebuild cycles that come from skipping the spec.

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