A COP decision is a document. That sounds deflating, but it is the good news: documents can be drafted, and text that is ready, short and specific has a real chance of surviving.
The work happens earlier than most people think. By the time the plenary meets, the useful sentences were written weeks before, by people who knew which contact group to bring them to.
This is the craft the Hub teaches: read the agenda, find the paragraph you can affect, and turn what you know into one sentence a delegate can defend.