Just want to clarify, this is not my Substack, I’m just sharing this because I found it insightful.
The author describes himself as a “fractional CTO”(no clue what that means, don’t ask me) and advisor. His clients asked him how they could leverage AI. He decided to experience it for himself. From the author(emphasis mine):
I forced myself to use Claude Code exclusively to build a product. Three months. Not a single line of code written by me. I wanted to experience what my clients were considering—100% AI adoption. I needed to know firsthand why that 95% failure rate exists.
I got the product launched. It worked. I was proud of what I’d created. Then came the moment that validated every concern in that MIT study: I needed to make a small change and realized I wasn’t confident I could do it. My own product, built under my direction, and I’d lost confidence in my ability to modify it.
Now when clients ask me about AI adoption, I can tell them exactly what 100% looks like: it looks like failure. Not immediate failure—that’s the trap. Initial metrics look great. You ship faster. You feel productive. Then three months later, you realize nobody actually understands what you’ve built.


I don’t get this argument. Isn’t the whole point that the ai will debug and implement small changes too?
Think an interior designer having to reengineer the columns and load bearing walls of a masonry construction.
What are the proportions of cement and gravel for the mortar? What type of bricks to use? Do they comply with the PSI requirements? What caliber should the rebars be? What considerations for the pouring of concrete? Where to put the columns? What thickness? Will the building fall?
“I don’t know that shit, I only design the color and texture of the walls!”
And that, my friends, is why vibe coding fails.
And it’s even worse: Because there are things you can more or less guess and research. The really bad part is the things you should know about but don’t even know they are a thing!
Unknown unknowns: Thread synchronization, ACID transactions, resiliency patterns. That’s the REALLY SCARY part. Write code? Okay, sure, let’s give the AI a chance. Write stable, resilient code with fault tolerance, and EASY TO MAINTAIN? Nope. You’re fucked. Now the engineers are gone and the newbies are in charge of fixing bad code built by an alien intelligence that didn’t do its own homework and it’s easier to rewrite everything from scratch.
If you need to refractor your program you might aswell start from the beginning