you can use :Eval! to evaluate under the cursor and replace it with the result. but if you mean *out* output, I'm not aware of a good way to do that in Fireplace. (I actually switched to Conjure partly to get a persistent log buffer like this.)

Thanks. Perhaps I'll raise a feature request after I've given it some thought

Try the :Last command after evaluating something

I don't use fireplace and instead I use conjure. This captures it by default but sometimes some of the messages also appear in the REPL buffer. So not fully bulletproof.