1. Unless you have a recent job that matches the exact same repair/service, you have incorrectly estimated the cost of the repair. In some states, this matters a lot and will cost the shop money. Unless your LLM only quotes for labor in sane amounts for diagnostic and nothing else, you’re only adding noise. This is a disservice to the client and the shop owner. The client now has an inaccurate quote for work and the shop will get a reputation for being inaccurate in quoting work.
2. Let’s say that you manage to get the exact same job twice. Your machine now needs to source parts. Parts may have been in stock yesterday. The might be out of stock now. If they are in stock, you need to retotal the price since prices are dynamic. Did you teach the agent how to source parts? What rules does it have for sourcing used parts?
3. New jobs can’t be quoted. Even if you taught the machine how to calculate book time and margins, it still has to find the right parts. If your shop does high end work, you know how much of a pain in the ass this is. Also remember that some work requires nonobvious parts - like fluids if you need to remove a part in the way of your goal.
4. The only area I see this being useful in is pickup. The shop can mark a car as done and the LLM can call to inform the client that they can come at a preset, unchanging time to get the vehicle. If the vehicle is staying overnight, the LLM can call with a progress update.
Finally, I’d like to note that this sort of dev work goes beyond hubris. It’s dangerous. The more we assume we know without verifying, the greater the risk. In this case, the dev is risking someone else’s livelihood.