---
title: "Prototype Showed the Design. Reviewers Said Validate First."
canonical: https://dxdev.com/blog/2026-09-08_prototype-validation-over-build/
datePublished: 2026-09-08
---
## Three verdicts, minutes apart

The first review said the funnel has no top. The third wrote: "Do not lead with MCP or cross-vendor portability. Both are materially less validated than the strategy assumes."

I read the verdicts as one complaint: we had built something on top of assumptions about customers that nobody had tested.

A plan like that can read as finished, tangible enough that you could hand it to someone and they'd believe it was already decided. That's the trap. A prototype that looks finished starts to feel true.

That's the cost of a convincing plan. Not money out the door, but the harder kind: time spent making a plan look right before checking whether it is.

## What "no top of funnel" actually meant

The first reviewer's line, that the funnel has no top, sounds abstract until you translate it. The document treated the blog as the top of the funnel, and the reviewer called that the thing we were most wrong about.

The third reviewer's point was the same shape of problem from a different angle. A technical fact that sounds like a selling point still has to be checked against what a customer cares about.

I read both as one root cause: confidence where there was little evidence.

## Why ask several readers at once

The useful move is to stop asking "does this sound right" and ask several readers "what's wrong with this" at the same time.

The slower, less satisfying fix is to ask actual people whether the assumptions in a plan are even in the neighborhood of true, before writing one more page that depends on them.

The prototype wasn't wrong because it was badly built. It was wrong because it was persuasive before it was tested, and persuasive is exactly the quality that makes you stop checking.