I can't speak authoritatively for all of history, but what's unique about the current ministry is that they have mandate letters that were made public.
On October 5th, 2017. See this statement in context.
On October 5th, 2017. See this statement in context.
October 5th, 2017 / 12:25 p.m.
Deputy Secretary to the Cabinet, Governance Secretariat, Privy Council Office
I can't speak authoritatively for all of history, but what's unique about the current ministry is that they have mandate letters that were made public.
See context to find out what was said next.