I attacked my own finance bot. The fix wasn't a better prompt.

Thank you. No, I did not tune it. But the "zero" needs a note. The hidden-text check alone flagged 12 of 60 runs (20%). Four bills have a hidden preview line, and the check flags them. A second read of the bill follows each flag. If the two reads agree, the bill goes through. This gives 0 false flags in 60. I tried a higher threshold. False flags fell, but detection fell from 8 of 8 to 1 of 8. So I kept the strict setting. The 60 runs are 20 test bills, each run 3 times. They are not real mail. The real rate is not known yet. A metric in production will show it.