"why?" is an interesting question. My best attempt at an explanation is that they have a poor sense of layout, especially in more than one dimension. That hidden time axis makes 1D problems like concurrency or memory fundamentally 2D+, and the results are then piss-poor unless I do a lot of the heavy lifting in the design. For that matter, they still frequently F it up and tell me it's perfect even with otherwise solid agentic patterns which can one-shot all kinds of other tasks, violating the spec I wrote to protect the agent from itself.

I don't have any justification for that explanation other than anecdotes. I will say that LLMs are typically quite bad at avoiding those memory issues, whatever the reason might wind up being.

I had the llms write an incredibly complex CV pipeline in zig through several iterations a and failed ideas and the only time it segfaulted was when I accidentally compiled it with avx intructions and deployed on a non-AVX machine