I remember using ocamlearlybird and the biggest issue was that you could pass options to your binary, appart from that it was great. I should open an issue for that.
I think we can give an option to specify cli arguments before run the executable. And an command to save the current debugging session to vscode launch configuration entry.
Yes dune integration would be good, but it was less of an issue for me. Not having it meant I had to find the executable myself, the launch.json file was slightly harder to write. Not being able to pass cli argument was far worse : it meant I was forced to modify the code of my project to provide default values.
You can specify arguments under the arguments key in the VSCode launch configuration as a list of CLI arguments. We might be missing nice user-facing documentation of this, but it’s specified in the launch configuration schema of VSCode OCaml Platform and is suggested for code completion.