Searching already isn't idempotent

idempotent != immutable

Search is idempotent in the sense that it doesn't change anything on the server, other than mutating caches (which should be idempotent).

Pretty sure nobody cares about ensuring that e.g. a proxy knows that nothing will go wrong if it issues a search twice. It's the reverse direction that matters.

Yes, this is why search is idempotent

Oh TIL. Thanks