Ugh, been there. I started putting a cheap programmable controller on my small kiln. Set the exact ramp and hold times, and it beeps at me for each step. Saved a few pieces from my own bad timing.
John Burton's book on kiln forming says 80% of failures come from rushed cooling cycles. He explains that glass needs steady temperature drops to relieve internal stress. Your piece probably cracked because the schedule was too fast. I heard some artists use backup timers to avoid this.
Going beyond just beeps, some controllers can log data to review later. You can check if the temperature drops matched your plan exactly. This helps spot patterns that might cause stress before a piece cracks!