Every AI-Generated Line of Code Is a Small Loan — And Eventually, You Have to Pay It Back

A bug showed up in my personal project last month. Nothing dramatic - a value wasn't updating the way it should have been.

I opened the file. I read it top to bottom. I had no idea what I was looking at.

Not because the code was badly written. It was clean. Well-organized. Doing exactly what I'd asked.

The problem was that I had never actually built a mental model of why it worked the way it did. I'd generated it, glanced at it, and moved on - dozens of times without ever once sitting with it long enough to understand it.

I couldn't fix a bug in my own project because I had never really owned the code I was fixing.

That was the moment I started thinking about AI-generated code differently: not as a gift, but as a loan.

It was a personal side project - nothing fancy just something I was building for myself in the kind of relaxed evening mode where you let AI drive more than you probably should. I'd describe what I wanted, it would generate the function I'd skim it see that it ran, and move to the next thing. For weeks, this felt like a superpower. I was building faster than I ever had.

The bug was the first bill that came due.

The Loan Nobody Told Me I Was Taking Out

Here's the mental model I wish I'd had earlier.

Every time AI generates code for you, it's not handing you something free. It's handing you something on credit. The code works today. The understanding the part that lets you debug it, extend it, explain it to someone else is the interest, and it's due whether you've budgeted for it or not.

The debt doesn't show up immediately. That's what makes it dangerous. It shows up later - as a bug you can't diagnose, a PR comment you can't answer, a feature you're afraid to touch because you're not sure what depends on it.

I'd been taking out this loan for weeks without realizing it. The bug was just the first bill that came due.

Why This Isn't Just a "Feeling" The Data Backs It Up

I went looking afterward, half expecting to find that I was just being paranoid. I wasn't.

Recent research on AI-assisted commits has found meaningfully higher rates of correctness and security issues compared to human-written code - the kind of issues that don't show up until someone actually exercises the code path that was never fully understood by the person who shipped it.

There's also a growing body of developer survey data pointing at something less technical and more personal: heavier reliance on AI coding tools correlating with higher reported burnout. Which tracks with what that evening actually felt like once the productivity high wore off not relief but a low-grade anxiety about a codebase I could no longer fully account for.

None of this means AI-assisted coding is bad. It means the debt is real, even when it's invisible, and pretending otherwise doesn't make it go away.

What I Actually Did - Slowly, Not Dramatically

I want to be honest here, because it would be easy to turn this into a bigger story than it was. I didn't delete everything and start over. I didn't swear off AI tools. That would have been its own kind of overcorrection.

What I actually did was slower and less satisfying to write about: I went through the file, section by section, and made myself understand it properly. Not skim it actually trace through what each part was doing and why, the way I would if a colleague had written it and left the company.

It took longer than fixing a bug in code I'd written myself would have. That was the whole point. The time I "saved" generating the code hadn't disappeared it had just been deferred to a moment of my choosing. Except I hadn't gotten to choose the moment. The bug chose it for me.

Once I actually understood the code, the fix took about ten minutes.

The Practice I Actually Kept

The thing that's stuck with me since isn't a dramatic rule. It's a small, boring habit:

Before I move on from anything AI generates, I ask myself one honest question could I explain this to someone else, right now, without looking at it again?

If the answer is no, I don't treat the task as finished. I read it again. I trace the logic. Sometimes I rewrite small pieces just to force the understanding to actually land, rather than passively wash over me.

My Rule: Before I move on from anything AI generates, I ask: Could I explain this to someone else, right now, without looking at it again?

If the answer is no, the task isn't finished.

It's slower in the moment. It's the only thing that's actually kept the debt from quietly piling back up.

I still use AI constantly. I'm not interested in pretending otherwise, and I don't think the answer is to use it less. The answer, for me, has been to stop treating "it runs" as the finish line, and start treating "I understand it" as the actual one.

The Honest Version of the Lesson

I'm not going to end this with a dramatic claim about who will or won't have a job in five years. I don't know that.

What I do know, from one bug in one personal project, is this: the code AI writes for you isn't free just because you didn't type it yourself. Somewhere down the line, something will ask you to account for it a bug, a question, a moment where you need to change it and realize you're not sure what you'd be changing.

You can pay that debt early, a little at a time, by actually understanding what you ship. Or you can pay it all at once, at 11 PM, staring at a bug in your own project, wondering how you got there.

I'd recommend the first one. I learned that the slow way.

Have you had a moment like this - where AI-generated code you'd shipped turned out to be a debt you didn't know you'd taken on? I'd genuinely like to hear how you noticed it, and what you did once you did. 👇