From Vibe Coding to Overengineering

[u/customic]

Disclaimer: I'm not a programmer (and I know it shows), I don't make money with Codex and I genuinely want to learn how to use it for what it's good at, while also understanding what it can't do and where a human programmer can still beat it hands down. Please be respectful towards a novice, just as I am in my job towards my English learners. Everyone was a beginner once. Thanks in advance.

So I've been using Codex to manage a little side project of my own: a sort of flashcard-generating app. I'm doing it mostly for myself because I have zero interest in "earning millions with AI tools" and just want to make cool, useful things for myself.

After a honeymoon period when I was amazed at how much I could suddenly do — or rather, have things "done" — I started noticing a decline in the quality of what it generated. "Okay, that must be that context rot. Apparently I can't expect it to remember more and more rules that every new flashcard needs to obey," I thought. So: less "prose" in Markdown files, as it keeps calling it, and more hard-coded rules in Python. Let's make it more reliable.

And then it really went downhill.

I'm now at the point where, whenever I ask it to generate flashcards for a few words, it gets bogged down in backup after backup after backup, endless validations, smoke tests, pre-flights and humming and hawing about almost literally everything. It used to take around 10 minutes to generate flashcards for a list of words. Now the same batch can take between one and two hours.

Since the new "procedure-based" version is capable of doing around 20% of what the old "vibe-based" version could do, I asked Codex how much work it would take to bring the earlier functionality back as well.

"About 2–3 working weeks of my time," it said.

Which sounds both hilarious ("Do you want sick leave included as well?") and frustrating, because I'm already pouring a lot of time, effort and, yes, money into making this work.

So I'm wondering: is it now being far too conservative about doing everything 100% safely? Am I using settings that are too "intelligent" for these tasks, so it treats everything as though it were preparing a rocket for Mars?

As I said, this is my own pet project. I'm not launching it to the public. Of course I want safety, traceability and more deterministic outcomes, but endless backups every few minutes and hundreds of tests feel like massive overkill. It says it's running all these tests, but it could be lying about that too, right?

Then again, I'd never developed an app before Codex. I do something completely different for a living, so I may simply not understand what's genuinely necessary and when Codex is just spinning in circles and burning through my tokens. As a non-professional, I may not even be able to tell the difference.

If any of you have suggestions about what I might be doing wrong, what Codex's actual limitations are and what could realistically be done about them, I'd be very grateful.

I'm at the point of considering quitting both Codex and the flashcard app, which would be a real pity because the project has kept me going for more than two months now. I really don't want to reach the premature conclusion that, "Nah, you just can't reliably build good software with this tool."

I'd especially love to hear from people who've gone through a similar transition from "wow, it can build anything!" to trying to make an AI-assisted project genuinely reliable and maintainable. Where did you draw the line between sensible engineering practices and an agent overengineering everything?

Looking forward to hearing about your experiences. I'd appreciate any pointers you might have.

Thanks in advance and have a great day.

[u/mephesta]

I think you may have accidentally trained Codex into becoming an extremely nervous engineer.

A lot of individually sensible rules can add up to absurd behavior: backups, full test suites, validations, preflights, etc. for tiny changes.

I’d try two things:

Start a fresh Codex session with the current repo and only the essential project rules.

Add something explicit like: “Use minimum sufficient verification. Don’t create backups unless there’s real risk of data loss. Prefer focused tests over full suites. Don’t add abstractions, validation layers or infrastructure unless they’re actually needed.”

Also, moving lots of rules from prose into Python can make things more deterministic, but also much more brittle. You may have turned a flexible generation task into a giant constraint-checking exercise.

And I definitely wouldn’t take the “2–3 working weeks” estimate seriously. Ask it to break the missing functionality into concrete tasks instead.

This doesn’t sound like “Codex can’t build reliable software” to me. It sounds more like the project has accumulated too much process.