Is it unethical for me to not tell my employer I've automated my job?

He could just say: "...hey, I've been working on automating this task, I think I got it working now."

If they're hourly, then yeah, billing 40 hours a week when you only did 2 is fraud. If salaried, I think it's okay.

Here's why: Individuals in the company will be good or bad, ethical or unethical. The company itself will (likely) be largely amoral and driven solely by a profit motive.

So when this person announces that he's automated himself out of a job, it sounds like it won't be a matter of 'great work, here's a cut of all the money you saved us and some more interesting work.' It'll likely be a matter of 'thanks, here's your contractually required severance.'

That is what it is, but if the company is allowed to be driven by profit motive, he should be too. It is within the best interests of his profit motive to continue with the automated work. For some reason when the person is an employee, it's no longer okay to be a sociopathic profit-motivated machine, we're actively disgusted by this type of behavior.

It seems like there should be a fairness principle in this situation when making a decision about things such as this that treats the employer and the employee as equals in a contractual obligation.

So, honestly, I don't think it would be wrong for the company, if they knew about the automation, to let the OP go and have the analysts themselves run the script. As a company, I don't think you should be required to pay someone to do a job that isn't necessary, even if the worker himself made the job unnecessary. I mean, we wouldn't be having the same discussion here if the company had instead hired someone (perhaps even the OP) on contract specifically to automate the job, and that was it.

I hesitate to suggest that what the OP is doing is unethical. I think aspects of it aren't quite above board: deliberately inserting bugs/mistakes to hide that it's now automated is, IMO, crossing the line. And at the end of the day, the company thinks they are paying the guy to do one thing, which they believe takes a significant chunk of time, but that's not the case. If he wasn't remote, and had to come into the office every day, his deception would probably be quickly found out, so in essence he's abusing his remote-work arrangement.

But hey, you gotta eat, and 1:1 time with a child is a great thing. Employers naturally have the advantage of a power imbalance, and it sounds like this guy lives in an area where tech jobs aren't aplenty.

I think my advice would be: well, the deed is done. Don't tell your employer yet, but start using your copious amounts of free time to search for a new job that also allows remote work, even if it takes several months to find one. Once you find something, give notice, and tell the employer that, as a parting gift, you automated the job, and give them the automation tool. At that point it's up to them what they want to do: hire another data entry monkey, or use the tool. Either way, I doubt this job would last forever (automated or otherwise), and then you'd just be out on your ass without any professional growth on record to use to help you get a new, better one.

Initiating this however would include involuntary, unpaid consultancy about what part of the company can be automated.