Thanks for the comments! We're working on the shortcuts but that should come soon. If you edit the code in the conversation before you hit run, it'll actually let you modify it and then run that code when you hit Run. (Try "Generate 10 normals in the console" and then change it to 20 when it gives rnorm(10).)

Can you say a bit more about what you mean with line-by-line running from a script? Would the script show up in the editor pane (top left) and then you'd run the script line by line and the AI would see the outputs from that code being run?