Start with BLUF, then put the context underneath
Start with BLUF (bottom line up front) and have your point in bold, then put the context underneath. Context AND details are both important.
When communicating through text, it's harder to clarify assumptions; getting the shared context is important.
Everyone is multi-tasking, context switching, and whatever they have primed in their head is going to be drastically different from where you're coming from.
The nice thing with chat, at least, is you can go back and see where things diverged, and rereading it helps you learn where you went wrong.
The not-so-nice thing is that you can't see someone's confused face, so you didn't even know that what you said needed clarifying.
So take a step back, be concise, and be picky about including what matters.