Saying what you chose, what you gave up for it, and when you would choose differently. If you can't name the cost of a decision, you probably didn't make it.
An agent will write a reasonable case for either side, so being able to recite one proves nothing. What it can't supply is the reason this was right for your project, and what would change your mind. Someone who only knows the upside has been told about the choice, and hasn't lived with it.
Say it to your agent
“Give me the strongest case against what I just decided: blocking merges on mutation score. Use what is in this repo and not general points. Then tell me what would have to be true for me to be wrong. Don't soften it, and don't finish by telling me I was right.”