Of course I do not know the initial ideas/philosophy of the launcher.

But the current implementation supports these custom commands (for whatever reason). Thus I'd say they should work "properly". My view of "properly" is that the implementation matches the documentation which is currently definitely not the case.

Of course one could add an extra passus to the docs like: "custom command names must not start with 'python'". But why include a special case (and make it less intuitive) without need?

By the way: We have a use case for this custom commands and I could image others had, too. Or how came that they were included?