Those boundary types

There are different types of boundary.

Type 1: about you
a. Stop doing X.
b. Start doing X.
c. Do X, but differently.

Type 2: about me
a. I can't.
b. I won't.

Type 2 is relatively easy, as their implementation is up to me. Flexibility around the margins and dynamic adaptability to circumstances are required.

Type 1 is harder to implement as it requires cooperation.

How to implement a type-1 boundary:

(i) Make a polite request
(ii) Offer a transaction ('If I ..., will you ...?')
(iii) Covertly alert them to a consequence
(iv) Overtly alert them to a consequence
(v) Use force

99.9% of the time, (1) and (2) are suitable.

(iii), (iv), and (v) are suitable rarely, e.g.

(iii) Not responding to aggressive texts but responding to pleasant ones.
(iv) 'If you carry on shouting, I will put the phone down.'
(v) Calling the police, blocking someone in electronic forms of communication and interactions including on social media, taking necessary action without consultation or permission, etc.

It is usually best to escalate to (iii), (iv), and (v) only once (i) and (ii) are thoroughly exhausted. I bear in mind that others have the right to turn down requests or offers.

In these situations, focus entirely if possible on future action, not on criticism of past action. This ensures the conversation is constructive and non-accusatory.