Insisting one last time 
I get that but I think it’s counterintuitive to have this as a default behavior. It’s quite rare to find commands that go upwards by default. Feels like a global side effect. As a teacher and sporadic developer of research tools, I’d rather have:
- at most upwards exporation until meeting a dune-project file (not dune-workspace)
subdir-like clauses in the said file to even avoid addingdunefiles anywhere (for simple projects; more complex projects may need specific dune files)- a clause in the dune-project file to allow going even more upwards (to accomodate the tool to the nice feature you describe)