I was at a professional conference a few days ago, and was surprised one of the presenters included a reference to Bill Eddy in his presentation on negotiations.
One major theme was the need to understand the opposing party in any sort of negotiation, and to that end had sections on different types of personalities... one was "Negotiating with High Conflict Individuals."
He referenced Bill Eddy's book and specifically the "BIFF" communication method in his talk "Brief Informative Friendly Firm"... and walked through a sample email response you can send using the method. It basically went something like "Thanks for your email, our position is XYZ, and bla bla bla. Thanks again. Goodbye."
I laughed imagining how many of us who have or had "high conflict" partners WISH we could "keep things brief..."
When my BPD wife is dysregulated, I do keep in BIFF, no matter how hard she tries to suck me into circular arguments. I have forced this into my new normal by enforcing my boundary of "all abuse must stop", even though she does not like it. I can personally attest keeping it BIFF does work, even though I am accused of doing a form of stonewalling.