Claim
A repair attempt is anything that interrupts the slide
A repair attempt is any move either of you makes mid-fight whose purpose is to stop the escalation rather than to win the point. A hand on an arm. "That came out worse than I meant." A joke you both recognize. "Can we start that again." A question you actually want the answer to.
They are usually clumsy. That is fine. A polished one is suspicious.
A repair attempt does nothing on its own, because it is a bid. What decides the next ten minutes is whether the other person takes it, which means half of this skill is not making them at all. It is accepting hers, while you are still angry, when taking it feels like surrendering an argument you were about to win.

Evidence
The bid is not the variable
In the Gottman lab's coded conflict tapes, the couples who stayed together were not distinguishable by how often they fought, or by how often someone tried to de-escalate. Both groups did plenty of both. The separating variable was whether the attempt landed, meaning whether the partner let it change the direction of the conversation.
The same body of work produced the much-quoted five-to-one ratio of positive to negative exchanges during conflict in stable couples. Hold that specific number loosely. It comes from observational samples of modest size, coded by people, and it was never a law.
Hold the structural finding tightly, because it is the one that changes your behavior tonight. You do not need a better line. You need to stop refusing hers.
Action
Take one
Your assignment in the next fight is to accept the first real repair attempt she makes, even if it is badly timed, even if you were two sentences away from a point you had been building all day.
Taking it looks like this. You stop. You answer the thing she offered rather than the thing you were halfway through. You do not add "but." One beat of visible slowdown is enough. Whether she registers it is not the point and not yours to predict; the fight stopping is.
You will lose an argument you could have won. That is the price and it is the correct price, because the argument was about dishes and what you bought with it is a household where de-escalation works. You can raise the dishes on Saturday. You cannot buy the other thing back cheaply.
Example
Marcus again, five weeks after the wedding argument on day one.
His repair attempts were all the same one. He would leave the room and come back with tea. It had worked for years, then it had stopped working, and his read was that Leila had hardened.
What the debrief surfaced was that the tea had become the entire apology, and the thing it stood in for had never once been said out loud. She had started refusing the tea, which he recorded as her escalating. From her side she was refusing a substitute, though she had never told him that either, and she said so.
He said the sentence instead, once, badly, in the kitchen on a Thursday. What he wrote afterwards: she took it immediately. I had been making tea for about six years.
Caution
The performed repair
There is a way to read today that produces something worse than the fight it was meant to end.
A man who treats this as a procedure starts performing it. He delivers the line in a level voice, he uses the phrase from the course, and she is now in an argument with a technique. Everyone can tell. It fails because a repair attempt works by showing her you would rather be close than right, and a performance demonstrates the opposite while saying the words.
Clumsy and real beats fluent and staged, every time. If the sentence you are about to say is one you have said in this exact form before, drop the form and say the awkward version. The awkwardness is the evidence.
Action
Debrief it the next day
A fight is not finished when it stops. Finish it the next day, on purpose, in ten minutes.
Three things get said and written down: what happened, in order; the one move each of you would do differently; and whether the subject still needs a decision or is closed. Date it. Keep it somewhere dull, a notes file or the back of a diary, and nowhere it could ever be waved at her.
The reason to write it is the reason this whole product writes things down. Without a record you remember the fight by how it felt, and how it felt is dominated by the worst ninety seconds. With a record you can see that the same subject has now come up four times since January, which is information neither of you had.
Aside
Repair can also be a door closed politely
The honest argument against all of the above: a repair attempt can be used to shut down a subject rather than to lower the temperature.
"Can we not do this" offered warmly at minute two is a repair attempt in shape and a refusal in function. Deploy it early and often and you will have a calm house with a list of undiscussed items in it, and one of you will be keeping that list.
So the test is not whether the fight stopped. It is whether the subject got finished, then or on a named later date. Repair buys a return to the topic in better condition. If it is buying permanent silence on four topics, the tool is being run backwards, whichever of you is running it. That is worth saying plainly, because she can do this too, and a man who has only been taught to watch for it in himself will sit on a list of his own.