Live data from Hacker News

Two things LLM coding agents are still bad at

kix.dev

171–180 of 382 posts

Re: Two things LLM coding agents are still bad at

#171
I think the issue with them making assumptions and failing to properly diagnose issues comes more from fine-tuning than any particular limitation in LLMs themselves. When fine tuned on a set of problem->solution data it kind of carries the assumption that the problem contains enough data for the solution.

What is really needed is a tree of problems which appear identical at first glance, but the issue and the solution is something that is one of many possibilities which can only be revealed by finding what information is lacking, acquiring that information, testing the hypothesis then, if the hypothesis is shown to be correct, then finally implementing the solution.

That's a much more difficult training set to construct.

The editing issue, I feel needs something more radical. Instead of the current methods of text manipulation, I think there is scope to have a kind of output position encoding for a model to emit data in a non-sequential order. Again this presents another training data problem, there are limited natural sources to work from showing programming in the order a programmer types it. On the other hand I think it should be possible to do synthetic training examples by translating existing model outputs that emit patches, search/replaces, regex mods etc. and translate those to a format that directly encodes the final position of the desired text.

At some stage I'd like to see if it's possible to construct the models current idea of what the code is purely by scanning a list of cached head_embeddings of any tokens that turned into code. I feel like there should be enough information given the order of emission and the embeddings themselves to reconstruct a piecemeal generated program.

Re: Two things LLM coding agents are still bad at

#172
post #37

Recently, I asked Codex CLI to refactor some HTML files. It didn't literally copy and pasted snippets here and there as I would have done myself, it rewrote them from memory, removing comments in the process. There was a section with 40 successive links with complex URLs. A few days later, just before deployment to production, I wanted to double check all 40 links. First one worked. Second one worked. Third one worke…

My custom prompt instructs GPT to output changes to code as a diff/git-patch. I don’t use agents because it makes it hard to see what’s happening and I don’t trust them yet.

Re: Two things LLM coding agents are still bad at

#173
A friendly reminder that "refactor" means "make and commit a tiny change in less than a few minutes" (see links below). The OP and many comments here use "refactor" when they actually mean "rewrite".

I hear from my clients (but have not verified myself!) that LLMs perform much better with a series of tiny, atomic changes like Replace Magic Literal, Pull Up Field, and Combine Functions Into Transform.

[1] https://martinfowler.com/books/refactoring.html [2] https://martinfowler.com/bliki/OpportunisticRefactoring.html [3] https://refactoring.com/catalog/

Re: Two things LLM coding agents are still bad at

#174
post #164

Earlier quoted context omitted.

> You’re just not using LLMs enough. > You can never trust the LLM to generate a url This is very poorly worded. Using LLMs more wouldn't solve the problem. What you're really saying is that the GP is uninformed about LLMs. This may seem like pedantry on my part but I'm sick of hearing "you're doing it wrong" when the real answer is "this tool can't do that." The former is categorically different than the latter.

It's pretty clearly worded to me, they don't use LLMs enough to know how to use them successfully. If you use them regularly you wouldn't see a set of urls without thinking "Unless these are extremely obvious links to major sites, I will assume each is definitely wrong". > I'm sick of hearing "you're doing it wrong" That's not what they said. They didn't say to use LLMs more for this problem. The only people that sho…

> If you use them regularly you wouldn't see a set of urls without thinking...

Sure, but conceivably, you could also be informed of this second hand, through any publication about LLMs, so it is very odd to say "you don't use them enough" rather than "you're ignorant" or "you're uninformed". It is very similar to these very bizarre AI-maximalist positions that so many of us are tired of seeing.

Re: Two things LLM coding agents are still bad at

#175
post #162

Earlier quoted context omitted.

Yeah so, the reason people use various tools and machines in the first place is to simplify the work or everydays tasks by : 1) Making the tasks execute faster 2) Getting more reliable outputs then doing this by yourself 3) Making it repeatable . The LLMs obviously dont check any of these boxes so why don´t we stop pretending that we as users are stupid and don´t know how to use them and start taking them for what th…

They easily check a bunch of those boxes. > why don´t we stop pretending that we as users are stupid and don´t know how to use them This is in response to someone who saw a bunch of URLs coming out of it and was surprised at a bunch of them being wrong. That's using the tool wrong . It's like being surprised that the top results in google/app store/play store aren't necessarily the best match for your query but actua…

The URLs being wrong in that specific case is one where they were using the "wrong tool". I can name you at least a dozen other cases from own experience, where too, they appear to be the wrong tool, for example for working with Terraform or for not exposing secrets by hardcoding them in the frontend. Et cetera. Many other people will have contributed thousands if not more similar but different cases. So what good are these tools then for really? Are we all really that stupid? Many of us mastered the hard problem of navigating various abstraction layers of computer over the years, only to be told, we now effing dont know how to write a few sentences in English? Come on. I'd be happy to use them in whatever specific domain they supposedly excel at. But no-one seems to be able to identify one for sure. The problem is, the folks pushing or better said, shoving down these bullshit generators down our throats are trying to sell us the promise of an "everything oracle". What did old man Altman tell us about ChatGPT 5? PhD level tool for code generation or some similar nonsense? But it turns out it only gets one metric right each time - generating a lot of text. So, essentially, great for bullshit jobs (i count some of the IT jobs as such too), but not much more.

Re: Two things LLM coding agents are still bad at

#176

Earlier quoted context omitted.

Well using an LLM is like rolling dice. Logits are probabilities. It is a bullshit machine.

Yeah, it read like "when running with scissors be careful out there". How about not running with scissors at all? Unless of course the management says "from now on you will be running with scissors and your performance will increase as a result".

And if you stab yourself in the stomach ... you must have sucked at running with the scissors :)

Re: Two things LLM coding agents are still bad at

#177
post #164

Earlier quoted context omitted.

It's pretty clearly worded to me, they don't use LLMs enough to know how to use them successfully. If you use them regularly you wouldn't see a set of urls without thinking "Unless these are extremely obvious links to major sites, I will assume each is definitely wrong". > I'm sick of hearing "you're doing it wrong" That's not what they said. They didn't say to use LLMs more for this problem. The only people that sho…

> If you use them regularly you wouldn't see a set of urls without thinking... Sure, but conceivably, you could also be informed of this second hand, through any publication about LLMs, so it is very odd to say "you don't use them enough" rather than "you're ignorant" or "you're uninformed". It is very similar to these very bizarre AI-maximalist positions that so many of us are tired of seeing.

This isn't ai maximalist though, it's explicitly pointing out something that regularly does not work!

> Sure, but conceivably, you could also be informed of this second hand, through any publication about LLMs, so it is very odd to say "you don't use them enough" rather than "you're ignorant" or "you're uninformed".

But this is to someone who is actively using them, and the suggestion of "if you were using them more actively you'd know this, this is a very common issue" is not at all weird. There are other ways they could have known this, but they didn't.

"You haven't got the experience yet" is a much milder way of saying someone doesn't know how to use a tool properly than "you're ignorant".

Re: Two things LLM coding agents are still bad at

#178
The “LLMs are bad at asking questions” is interesting. There are some times that I will ask the LLM to do something without giving it All the needed information. And rather than telling me that something's missing or that it can't do it the way I asked, it will try and do a halfway job using fake data or mock something out to accomplish it. What I really wish it would do is just stop and say, “hey, I can't do it like you asked Did you mean this?”

Re: Two things LLM coding agents are still bad at

#179
post #37

Recently, I asked Codex CLI to refactor some HTML files. It didn't literally copy and pasted snippets here and there as I would have done myself, it rewrote them from memory, removing comments in the process. There was a section with 40 successive links with complex URLs. A few days later, just before deployment to production, I wanted to double check all 40 links. First one worked. Second one worked. Third one worke…

5 minutes ago, I asked Claude to add some debug statements in my code. It also silently changed a regex in the code. It was easily caught with the diff but can be harder to spot in larger changes.

I asked Claude to add a debug endpoint to my hardware device that just gave memory information. It wrote 2600 lines of C that gave information about every single aspect of the system. On the one hand kind of cool. It looked at the MQTT code and the update code, the platform (esp) and generated all kinds of code. It recommended platform settings that could enable more detailed information that checked out when I looked at the docs. I ran it and it worked. On the other hand, most of the code was just duplicated over and over again ex: 3 different endpoints that gave overlapping information. About half of the code generated fake data rather than actually do anything with the system.

I rolled back and re-prompted and got something that looked good and worked. The LLMs are magic when they work well but they can throw a wrench into your system that will cost you more if you don't catch it.

I also just had a 'senior' developer tell me that a feature in one of our platforms was deprecated. This was after I saw their code which did some wonky hacky like stuff to achieve something simple. I checked the docs and said feature (URL Rewriting) was obviously not deprecated. When I asked how they knew it was deprecated they said Chat GPT told them. So now they are fixing the fix chat gpt provided.

Re: Two things LLM coding agents are still bad at

#180
One thing LLMs are surprisingly bad at is producing correct LaTeX diagram code. Very often I've tried to describe in detail an electric circuit, a graph (the data structure), or an automaton so I can quickly visualize something I'm studying, but they fail. They mix up labels, draw without any sense of direction or ordering, and make other errors. I find this surprising because LaTeX/TiKZ have been around for decades and there are plenty of examples they could have learned from.
Post reply on HN