Specs-Driven vs Prompts-Driven: Thoughts From Recent Chats With Builders

Hey folks — Ryan here

I’ve been chatting with a bunch of vibe-coding builders lately, and everyone keeps saying the same thing:

Prompts get you UI fast — but the moment things get real, everything starts to fall apart.

they told me:

• “I’m rewriting prompts all day because the logic drifts.”

• “Looks good, but the flow makes no sense.”

• “I’m vibe-coding… but also vibe-debugging.” 😅

And it hit me:

Prompts give you speed.

Specs give you control.

You need both, but right now most tools only give you the first one.

When products get states, rules, edge cases, handoffs…

prompt-driven workflows just break.

Context gets lost, UI and logic go out of sync, agents reinvent things, nothing stays aligned.

So I started asking myself:

What if vibe-coding was specs-driven, not prompts-driven?

What if structure — not prompts — was the real foundation?

That’s the direction my team and I have been exploring:

an AI PM + AI Designer working together on one canvas,

keeping richer specs (PRDs, flows, UI, and prototypes) aligned while you build.

Curious how you all deal with this:

• Where does your vibe coding usually lose control?

• Do you write specs first, or go straight into prompting?

• What kind of structure would make your builds more stable?

Would love to hear your experiences