My customer argues with me because ChatGPT told them something different. How do I handle it without losing the job?

The instinct is to defend your expertise. That is the losing move, because it turns the conversation into your word against a machine that sounds certain and never gets tired. The customer is not really challenging you — they are trying not to get ripped off, and AI just gave them what feels like a second opinion for free.

So start by agreeing with what they actually want: a job done right at a fair price. Then move straight to the specific thing the model could not have known. It has not seen their panel, their soil, their roof, or the amendment your municipality adopted last year. General training data cannot describe a particular building.

Say the specific thing out loud and then put it in writing — a photo, the clause number, the utility bulletin. Written specifics end this conversation; tone never does. A short note that says "here is the local rule, here is what I found on site, here is why the number is what it is" costs you five minutes and saves the job.

One more thing worth knowing: models blend national code, local amendments and utility rules into a single confident answer. That blending is the actual failure, and it is the most damaging one in a regulated trade. Being able to name it calmly is what makes you sound like the professional in the room.