I don't see an especially clear way forward here:

We could just let arc ignore these autotarget failures; we already prompted the user when they created the diff. However, the autotarget failures cause a failure on the Buildable, and we currently care about the state of the buildable, so this isn't trivial (the client would need to deduce that the Buildable state was a consequence of the autotarget failures alone, which doesn't feel very good).

We could make autotarget failures not fail the buildable, although this feels sort of bad/incorrect.

We could rename the "Arcanist Client Results" autoplan to "Unit and lint results implicitly generated by arc unit and arc lint when you typed arc diff".

We could ignore the failure state of the buildable and only prompt on build failures, excluding the arc autoplan. Maybe this is fine, but it probably gets into trouble later if builds are permitted to fail without impacting the buildable.

Maybe renaming "Arcanist Client Results to "arc lint + arc unit" would be clear enough? It sounds like this workflow is generally fine, users are just not making the connection between "Arcanist Client Results" and the "arc" client?

Renaming to arc lint + arc unit sounds good and clearer to me.