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> what they cannot do is maintain clear mental models

The more I use claude code, the more frustrated I get with this aspect. I'm not sure that a generic text-based LLM can properly solve this.

It's good at micro, but not macro. I think that will eventually change with smarter engineering around it, larger context windows, etc. Never underestimate how much code that engineers will write to avoid writing code.
> We don't just keep adding more words to our context window, because it would drive us mad.

That, and we also don't only focus on the textual description of a problem when we encounter a problem. We don't see the debugger output and go "how do I make this bad output go away?!?". Oh, I am getting an authentication error. Well, meaybe I should just delete the token check for that code path...problem solved?!

No. Problem very much not-solved. In fact, problem very much very bigger big problem now, and [Grug][1] find himself reaching for club again.

Software engineers are able to step back, think about the whole thing, and determine the root cause of a problem. I am getting an auth error...ok, what happens when the token is verified...oh, look, the problem is not the authentication at all...in fact there is no error! The test was simply bad and tried to call a higher privilege function as a lower privilege user. So, test needs to be fixed. And also, even though it isn't per-se an error, the response for that function should maybe differentiate between "401 because you didn't authenticate" and "401 because your privileges are too low".

[1]: https://grugbrain.dev

> We don't see the debugger output and go "how do I make this bad output go away?!?"

In the past, I've worked with developers that do. You ask them to investigate and deal with an error message, and all they do is whatever makes the error go away. Oh, a null pointer exception is thrown? Lets wrap it in a try/catch and move on.

> Oh, I am getting an authentication error. Well, meaybe I should just delete the token check for that code path...problem solved?!

If this is how you think LLMs and Coding Agents are going about writing code, you haven't been using the right tools. Things happen, sure, but also mostly don't. Nobody is arguing that LLM-written code should be pushed directly into production, or that they'll solve every task.

LLMs are tools, and everyone eventually figures out a process that works best for them. For me, it was strongs specs/docs, strict types, and lots of tests. And then of course the reviews if it's serious work.

Literally had a situation where cursor decided the best course of action in the situation was to delete the authentication test to solve the problem.
I am not a fan of today's concept of "AI", but to be fair, building today's software is not for the faint of heart, very few people gets it right on try 1.

Years ago I gave up compiling these large applications all together. I compiled Firefox via FreeBSD's (v8.x) ports system, that alone was a nightmare.

I cannot imagine what it would be like to compile GNOME3 or KDE or Libreoffice. Emacs is the largest thing I compile now.

Yeah, I think it's pretty clear to a lot of people that LLMs aren't at the "build me Facebook, but for dogs" stage yet. I've had relatively good success with more targeted tasks, like "Add a modal that does this, take this existing modal as an example for code style". I also break my problem down into smaller chunks, and give them one by one to the LLM. It seems to work much better that way.
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I think most people trying to touch on this topic don't consider this byline with other similar bylines like, "Why LLMs can't recognize themselves looping", or "Why LLMs can't express intent", or "Why LLMs can't recognize truth/falsity, or confidence levels of what they know vs don't know", these other bylines basically with a little thought equate to Computer Science halting problems, or the undecidability nature of mathematics.

Taken to a next step, recognizing this makes the investment in such a moonshot pipedream (overcoming these inherent problems in a deterministic way), recklessly negligent.

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> Context omission: Models are bad at finding omitted context.

> Recency bias: They suffer a strong recency bias in the context window.

> Hallucination: They commonly hallucinate details that should not be there.

To be fair, those are all issues that most human engineers I've worked with (including myself!) have struggled with to various degrees, even if we don't refer to them the same way. I don't know about the rest of you, but I've certainly had times where I found out that an important nuance of a design was overlooked until well into the process of developing something, forgotten a crucial detail that I learned months ago that would have helped me debug something much faster than if I had remembered it from the start, or accidentally make an assumption about how something worked (or misremembered it) and ended up with buggy code as a result. I've mostly gotten pretty positive feedback about my work over the course of my career, so if I "can't build software", I have to worry about the companies that have been employing me and my coworkers who have praised my work output over the years. Then again, I think "humans can't build software reliably" is probably a mostly correct statement, so maybe the lesson here is that software is hard in general.

I think they're another tool in the toolbox not a new workshop. You have to build a good strategy around LLM usage when developing software. I think people are naturally noticing that and adapting.
These LLM discussions really need everyone to mention what LLM they're actually using.

> AI is awesome for coding! [Opus 4]

> No AI sucks for coding and it messed everything up! [4o]

Would really clear the air. People seem to be evaluating the dumbest models (apparently because they don't know any better?) and then deciding the whole AI thing just doesn't work.

> LLMs get endlessly confused: they assume the code they wrote actually works; when test fail, they are left guessing as to whether to fix the code or the tests; and when it gets frustrating, they just delete the whole lot and start over.

I feel personally described by this statement. At least on a bad day, or if I'm phoning it in. Not sure if that says anything about AI - maybe just that the whole "mental models" part is quite hard.

LLMs can’t build software because we are expecting them to hear a few sentences, then immediately start coding until there’s a prototype. When they get something wrong, they have a huge amount of spaghetti to wade through. There’s little to no opportunity to iterate at a higher level before writing code.

If we put human engineering teams in the same situation, we’d expect them to do a terrible job, so why do we expect LLMs to do any better?

We can dramatically improve the output of LLM software development by using all those processes and tools that help engineering teams avoid these problems:

https://jim.dabell.name/articles/2025/08/08/autonomous-softw...

>If we put human engineering teams in the same situation, we’d expect them to do a terrible job, so why do we expect LLMs to do any better?

Because LLMs were trained for one shot performance and they happen to beat humans at that.

> If we put human engineering teams in the same situation, we’d expect them to do a terrible job, so why do we expect LLMs to do any better?

Counterpoint: projects by autonomous solo developers are often excellent, and these can only exist exactly because said developers directed themselves in that exact way.

I think I agree with the idea that LLMs are good at the junior level stuff.

What's happened for me recently is I've started to revisit the idea that typing speed doesn't matter.

This is an age-old thing, most people don't think it really matters how fast you can type. I suppose the steelman is, most people think it doesn't really matters how fast you can get the edits to your code that you want. With modern tools, you're not typing out all the code anyway, and there's all sorts of non-AI ways to get your code looking the way you want. And that doesn't matter, the real work of the engineer is the architecture of how the whole program functions. Typing things faster doesn't make you get to the goal faster, since finding the overall design is the limiting thing.

But I've been using Claude for a while now, and I'm starting to see the real benefit: you no longer need to concentrate to rework the code.

It used to be burdensome to do certain things. For instance, I decided to add an enum value, and now I have to address all the places where it matches on that enum. This wasn't intellectually hard in the old world, you just got the compiler to tell you where the problems were, and you added a little section for your new value to do whatever it needed, in all the places it appeared.

But you had to do this carefully, otherwise you would just cause more compile/error cycles. Little things like forgetting a semicolon will eat a cycle, and old tools would just tell you the error was there, not fix it for you.

LLMs fix it for you. Now you can just tell Claude to change all the code in a loop until it compiles. You can have multiple agents working on your code, fixing little things in many places, while you sit on HN and muse about it. Or perhaps spend the time considering what direction the code needs to go.

The big thing however is that when you're no longer held up by little compile errors, you can do more things. I had a whole laundry list of things I wanted to change about my codebase, and Claude did them all. Nothing on the business level of "what does this system do" but plenty of little tasks that previously would take a junior guy all day to do. With the ability to change large amounts of code quickly, I'm able to develop the architecture a lot faster.

It's also a motivation thing: I feel bogged down when I'm just fixing compile errors, so I prioritize what to spend my time on if I am doing traditional programming. Now I can just do the whole laundry list, because I'm not the guy doing it.

A lot of this sounds like Claude is making up for bad tooling?

Machine refactoring has been a thing for decades now but only for mainstream strongly-typed languages in major IDEs. You can do massive refactorings in seconds that always compile perfectly.

LLMs are picking up the slack for js/ts, which is great, but pretty sad that we need this much compute to do something that took seconds 20 years ago in other languages.

They can read and mind the error then figure out the best way to resolve. It is the best part about llm. No human can do it better than an llm. But they are not your mind reader. It is where things fall apart.
Most of this might be true for LLM's but years of investing experience has created a mental model of looking for the tech or company that sucks and yet keeps growing.

People complained endlessly about the internet in the early to mid 90s, its slow, static, most sites had under construction signs on them, your phone modem would just randomly disconnect. The internet did suck in alot of ways and yet people kept using it.

Twitter sucked in the mid 2000s, we saw the fail whale weekly and yet people continued to use it for breaking news.

Electric cars sucked, no charging, low distance, expensive and yet no matter how much people complain about them they kept getting better.

Phones sucked, pre 3G was slow, there wasn't much you could use them for before app stores and the cameras were potato quality and yet people kept using them while they improved.

Always look for the technology that sucks and yet people keep using it because it provides value. LLM's aren't great at alot of tasks and yet no matter how much people complain about them, they keep getting used and keep improving through constant iteration.

LLM"s amy not be able to build software today, but they are 10x better than where they were in 2022 when we first started using chatgpt. Its pretty reasonable to assume in 5 years they will be able to do these types of development tasks.

..."(at least for now) you are in the drivers seat, and the LLM is just another tool to reach for."

Improvements in model performance seem to be approaching the peak rather than demonstrating exponential gains. Is the quote above where we land in the end?

Am I the only one continuously astounded at how well Opus 4 actually does build mental models when prompted correctly?

I find Sonnet frequently loses the plot, but Opus can usually handle it (with sufficient clarity in prompting).

Only because most AI startups are doing it wrong.

I don't want a chat window.

I want AI workflows as part of my IDE, like Visual Studio, InteliJ, Android Studio are finally going after.

I want voice controlled actions on my native language.

Knowledge across everything on the project for doing code refactorings, static analysis with AI feedback loop, generating UI based out of handwritten sketches, programming on the go using handwriting, source control commit messages out of code changes,...

Recently, i found lots of fun with codex-cli of openai, which even works as a mere ChatGPT Plus subscriber. :)
Well, welcome to the club of awareness :)
I wonder if some of this can be solved by removing some wrongly setup context in LLM. Or get a short summary, restructure it and againt feed to a fresh LLM context.
> "when test fail, they are left guessing as to whether to fix the code or the tests"

I've one thing that helps is using the "Red-Green-Refactor" language. We're in RED phase - test should fail. We're in GREEN phase - make this test pass with minimal code. We're in REFACTOR phase - improve the code without breaking tests.

This helps the LLM understand the TDD mental model rather than just seeing "broken code" that needs fixing.