Author argues that values long embedded in Ruby culture (testing, readability, design) are very useful for collaborating with AI, gives an example os asking Claude to follow tdd
You mean "not statically typed". Which also applies to Javascript, PHP, Python, ... so if that critique doesn't stick to those, it's not a critique you can level at Ruby.
But it does have extremely powerful metaprogramming capabilities which are regularly abused by those not wise enough to know that just because you could do something doesn't mean that you should.
I regularly code in a variety of languages from C / C++ through Python and Ruby through to Haskell. They all have their advantages and disadvantages. All of them are capable of abuse by the sufficiently determined. And unit tests are helpful in all of them.
I’ve worked on rails apps for the last 9 years and I’d guess 80% of the bugs that show up on production would have been flagged by typescript.
Which is what the Ruby test-heavy culture is all about. I prefer types for this very reason; the compiler/checker is a complete suite of testing I don't have to write.