How a Missing book_id Kwarg Quietly Tanked My Inverted-Alpha Paper Trade

Executive summary I ran an inverted-alpha paper-trading experiment to test whether inverting my live signals would produce net-positive P&L over 100 round-trips. The inverted-alpha book (Book 2) hit a 63% win rate — good enough to celebrate — but the per-trade average loss was six times larger than the per-trade win size. The shape of the P&L didn't match any thesis I had. After a few days of staring at the numbers, I traced the problem to a single missing keyword argument in the close-o