Unless I've missed something: We didn't make any agreements as to the practicalities, only the outcomes. The agreement was no material changes to the situation in Norther Ireland. That requires either a border between Northern Ireland and UK, or harmonized rules between UK/NI + Europe. Post December the Tories made all types of claims as to the "hardness" of Brexit, all of which ignored the agreement which had been drafted in December.
As far as I can tell, what's happening now is a reiteration and continuation on the details of the December agreement. That is, Europe is actually doing work to move things forward. The UK remains exactly where it was before December despite having signed up to a number of agreements.