I've progressed in using latest Claude-kins and the GPTs as usually competent teammate/buddies, and generally know to sort out the fluff confidence with the realz (shoot, that was how I was when I was but a wee little coder lad: overconfident because of an error-free compile and one non-segfault run.)

You have to put in the time, the skill creation, the system prompt/personalization, the (sometimes adversarial) automation, the testing, verification, kicking down the loop castles (as usually caused by being cheeky with highest effort levels.)