Seems very good at it; for a while in my F# project I didn't know how to tell claude code on the web how to install it, but claude still made code that worked fine - its COT said, paraphrasing: "no F# compiler here so I will check this code by inspection". Later I learned how to make F# available there - in claude.md tell it to install the ubuntu dotnet runtime via apt, which includes F#. May not be needed anymore though.