so it just boils down to strictness even when we're talking LLMs?

I agree with you about fast failure being a nice feature , but I also think that if you're TDDing a bunch of stuff and it fails in some categorical way , well then the test suite was lazy.

> so it just boils down to strictness even when we're talking LLMs?

The article describes what I've been doing for the past few months - I did small python projects in the past because of the ecosystem: I couldn't possibly write a ton of the stuff required for the things I wanted to do, so I leaned into python because someone already wrote it for me. Quality of deps was mostly ok for the happy paths, but always a chore to patch the broken ones.

Nowadays I tell Claude what I want to build and I always ask it whether rust is a good choice for it. It'll pick up the right crates or choose whether it should DIY, do all the plumbing, nail all the logic, and in ~30m I'll have something very solid that would have taken me 3+ weeks of part-time evening coding in python. I think the article is right and rust is the closest to the "best language" we have for LLM coding at the moment: the strict typing and the tooling dramatically reduce the output space for LLMs, and 99% of errors have a clear, precise explanation that is actionable, and the compiler helps you a lot there too.

I think it also boils down to the fact that you cannot reliably and quickly answer "why is this arg None?" in languages like python without figuring out the call graph and evaluating possible states and inputs/outputs. Rust makes all that explicit and forces you handle it, which I feel dramatically cuts the time an LLM needs to spend figuring out why it's broken or what to do next. EDIT: The fact that you get memory safety on top of all this and it's handled by the compiler is yet another advantage for LLMs: the logic that gets written is simpler to reason about, because if you try to mutably access the same variable in two different places, the compiler will feed this back to the LLM at build time. In other languages that would be a "code smell" or would require static analysis.

Strictness is a quality for software and a chore for humans, and of course the stricter you are at representing your logic and your state machine, the less ways a program can break. LLMs writing in rust give you the strictness without the chore part, and it's a very good deal from my point of view.

If you are using TDD with any recent model and even local models (qwen3.5+), you alleviate most of the issues mentioned.

Note that:

Writing code, then tests

Is not equivalent to:

Writing tests, then code