[oakpond]

Sort of agreed. Natural language specs don't scale. They can't be used to accurately model and verify the behavior of complex systems. But they can be used as a guide to create formal language specs that can be used for that purpose. As long as the formal spec is considered to be the ground truth, I think it can scale. But yeah, that means some kind of code will be required.. :)

[j45]

Things like Github's speckit seems to have a fair amount of usage.

The idea that specs are code now, is one can effectively rebuild in the future with newer models. Test requirements could be defined upfront in the specs too, no?

[oakpond]

I think natural language leaves too much room for ambiguities. If you treat it as code I expect you will run into frequent bugs and unintended side effects of LLM-authored changes as your software evolves. So I'm skeptical about this approach.

A formal language helps in this regard because it makes visible the inconsistencies that are hidden in the specifications.

Coding is difficult sometimes because it turns out the problem you are trying to solve is more difficult than expected (not because it's difficult to code).

[j45]

Sounds like this perspective is theoretical.

Been building for a long time, and more specifically overseeing building in detail, which transfers interestingly to overseeing LLMs.

Just like with coworkers, providing the right amount of context (not too much, or too little) for the request to succeed is critical.

I shared similar views, but I have seen first hand (using in production myself) that specs, well done in a way for LLMs, can do development with AI that works. If something doesn't work out, you don't fix the code, you adjust the spec. Highly recommend watching doers on Youtube who are sharing screens.

Discovering a problem is more difficult than expected allows you to take more shots at it, quicker by adjusting the spec, for example and running again. We are used to just plowing ahead to make the code right, instead of improving/clarifying the ask/spec.

[oakpond]

In my experience, when you sell expensive complex systems, customers are very worried about any differences in system behavior as a result of software updates.

When you implement a new feature with these tools, how do you convince yourself that existing system behavior remains unchanged?

When you have the code in front of you, atleast you can reason about the full system behavior before and after because code is unambiguous like that.

With spec driven development, the LLM can rewrite anything as long as it meets the spec. That's a problem if your customer relies on behavior that's written down ambiguously (or omitted entirely).

So, I think this is only going to work if you write specs with mathematical precision.. at which point you probably want to write them using a mathematical language.

[j45]

Appreciate learning from your perspective.

I've built, integrated and sold expensive complex systems. They want it working, connected, and reliable. Lots of paths there.

Have you built with LLMs? I'm asking because I would refer to things from having something working on a complex code base.

Specifications, or inputs in a way are a new code. The added focus on documentation, before and after is a bonus too, and also helps with alignment.

Code styles/formats/philosophies can be documented and followed.

The human process of what to look into, in what way, for what areas of the code base, can also be trained and remembered. There are ways to achieve and maintain precision without 100% mathematical precision, because there are only so many ways to solve a problem, or step and the mechanisms for deciding can also be defined in general, or specific.

[oakpond]

I build with LLMs all the time but I generally don't do vibe coding unless it's something small I don't really care about.

When I look at SpecKit, I see a kind of vibe coding fantasy: "code is no longer king", stop writing "undifferentiated code." There is no code on the site, just a bunch of prompts and commands.

On the other hand, what you are describing above is bringing specs closer to the codebase, while not replacing the code itself. Like I said I have no problems using natural language as a guide (even as a primary guide). I also completely agree that it helps with documentation.

My main point is: if you want to maintain a complex system, you also need to have an accurate description of the system behavior in some kind of formalism.

This kind of description reflects the true system behavior better. It's more helpful when you need to predict the impact of changes and also during debugging.