I used Claude to automate my tax this year instead of my accountant and it was more accurate

I still use a CPA but check his work using Claude. A CPA's mistake costs you less than your own LLM's mistake, because the CPA is liable for theirs.

That’s definitely not always the case. My CPA made a mistake on my state taxes and they explicitly told me I was liable because it was my tax filing. I suppose they could have been lying to me but I doubt it.

Different level of "liable".

Yes, you are, in the end, responsible for your own taxes the filings. If a mistake was made and you owe additional taxes, you have to pay them as well as any penalties, etc. But if you used a CPA, you have the option to sue to recover any loss they caused you through negligence.

How did you measure that accuracy?