[tikhonj]

Sounds like OxCaml is pretty close to what you want. You get access to similar capabilities as Rust, but also stricter typing and an (optional) effect system. I don't know of an equivalent to Liquid Types, but it seems like the same approach that worked for Haskell would work naturally in OxCaml.

[SwellJoe]

You need a huge corpus of training data for the language for models to be good at using it. Rust has that (so does Go). OxCaml probably does not (unless there's some iceberg of open code out there that I'm unaware of). I'll take a slightly sub-optimal language with excellent training data coverage of my use case over a perfect language that the models have barely seen 100% of the time.

Which is why I think it's silly to suggest creating a new language "for agents". Unless one or more of the frontier AI companies commit to creating a language and the training corpus for a new language, there's no good way to bootstrap a language that is ideal for agents. You need the huge pile of high quality code as a prerequisite for a language being good for agents. And, the argument applies similarly poorly for some language that looks like it has a good shape for agents, if it doesn't have a lot of human written code from the past decade or whatever. It's not a good language for agents unless agents already know the language really, really, well because of a huge pile of code in that language in its training data.