Comment by TeMPOraL

> Early lesson I learned from AI engineering was - there is no substitute to giving a groomed epic to an agent. Instead of simply saying 'implement themes in my product' you need to be specific, in fact more specific than usual.

I think this lesson is getting partially outdated. Yes, you need to be specific about what you want, and with earlier LLMs, you need to had both domain knowledge and some general software development experience to front-load various big and small choices about design, architecture and operational reality - what libraries to use, how system components communicate, how you handle auth and store secrets, etc. Otherwise the LLM would pull some random mix of ideas from its latent space, and give you something that's broken in really stupid ways.

Nowadays, it doesn't feel like that to me, not anymore. I still need some understanding to verify the proposals, but I found the last ~6 months of SOTA models to make good choices. Like, just yesterday I asked Claude to design me some simple service, and focused on explaining it the domain parts (nature of systems I want to integrate together, the purpose of that, and the user's priorities and use cases), and the design I got back had specific suggestions around security, authentication, deployment, failover, integration, behavioral impedance-matching between integrated systems, and more, that I all recognized as based on solid software engineering and ops practices, but deviating from it explicitly in every place where it would be wrong for this specific project. The model considered way more corner cases than I did, and I'm actually really impressed by it.

But then, I find greenfield development is easy with LLMs. Modifying existing systems, especially legacy ones, is where I need to babysit and micromanage models - because any misunderstanding or inaccuracy, which often comes from stale documentation or naming mistakes, tends to get amplified and confuse the agents. No matter how precisely you specify your epic, if the model will find something that contradicts your knowledge/intent, there are good chances it'll get confused and make subtle errors, and you won't realize until much later.

The way I see it: models are highly biased to treat everything they read as "ground truth", all of equal importance. There's no nuanced notion that some information may be stale, that there's a temporal and causal order to sources, and that some information may just be wrong.

And this compounds when you let your LLM write code and documentation over time.