From Cambridge Dictionary:
provide against something
phrasal verb with provide verb
to make plans in order to prevent or deal with a bad situation
From OLD:
provide against phrasal verb
provide against something
(formal) to make preparations to deal with something bad or unpleasant that might happen in the future
From M-W:
provide against
verb
to do what is needed to prepare for (something bad that might happen)
From Longman:
provide against something
phrasal verb [transitive] formal
to make plans in order to deal with something that might happen
From OED:
I.2. c1425– intransitive. To take appropriate measures in view of a possible event; to make adequate preparation for the future. Frequently with against, for.
From Collins:
(intr; often foll by for or against)
to take careful precautions (over)
She provided against financial ruin by wise investment
Four dictionaries classify "provide against" as a phrasal verb used to make preparations for unpleasant events, and they categorise it as a formal expression rather than an idiom. Cambridge, OLD, Merriam-Webster, and Longman treat the combination as transitive, whereas the OED and Collins describe "provide" as intransitive when followed by "against".
Within "provide against something", should I regard "provide against" as a complete transitive verb, or should I analyse the individual function of "provide"?