doc problem How to add thread-level persistence to subgraphs

[miniboxhaha]

doc
I think there might be some misleading information here.
for example,

and here is a problem:
question1,3 is relevant to weather node
question2 is relevant to food node
so if use state.messages call invoke, Irrelevant information was conveyed to subnode.
but if use state.instructions, weather node do not know where to update.

At the moment, I'm dealing with it by set checkpointer and configurable: { thread_id: "1" } to every subnode.
which is not mentioned by doc.
but i am not sure is the right way.

can anyone help? thanks!!!