Four options for a 401(k) from a job you left, the 20% withholding that turns a $50,000 check into $40,000, and three cases where an IRA costs you.
An HSA vs FSA prompt run cold: the AI reframed it as a choice between two health plans, then quoted a 2027 HSA limit $50 above the published one.
A ChatGPT prompt to size your September 15 estimated tax payment on $30,000 of 1099 income. The safe harbor came out to $465, not $7,500.
A ChatGPT prompt to choose Roth or traditional 401(k) in 2026, run on a $92,000 salary. The break-even retirement rate is 19.3%, not 22%.
I ran one 2026 pay stub and my W-4 through Claude. It found a stale dependent credit and a $2,910 shortfall, with eight paychecks left to fix it.