Agreeing that the anger should not disrupt human contact and safety is absolutely essential, and does not require resolving the anger itself. It is certainly easier to successfully resolve anger and conclude the topic than to being asked to set aside anger for the evening. However, resolving anger when tired, stressed out, after a long day for one or both of you, and maybe hungry — at significant personal cost to one or both of you — is not a success. It does not create a space of safety for future arguments, and it implies that anger is a higher priority than the human being(s) feeling it.
The ceasefire specifically does not include any form of warfare between when the agreement is made and the next day. No passive-aggressiveness, no sniping, no laying verbal traps. No silent punishment. No withholding platonic touch because "they don't deserve a hug". If they attempt to start something, let it slide. If you attempt to start something, stop the instant you realize it and apologize for breaking the ceasefire.
You don't have to hide the signs of your anger. You don't have to make them feel better. You don't have to do everything they ask out of guilt. But you must continue to be their partner, and sustain the foundation of your relationship, by offering them safety overnight.
Note: This applies exclusively to non-abusive anger. If you feel like you're being verbally, emotionally, or physically abused, whether anger is involved or not, please seek immediate support from a hotline, a friend, a professional, anyone. If you can get out, do so. Possessions can always be replaced.
(Standard disclaimer, I am not your medical professional.)