I let an agent run unattended overnight. At 3am it emailed 400 customers the wrong thing.

A developer shares a cautionary tale about the dangers of 'set it and forget it' automation. After scheduling an unattended script to reconcile payments and email customers about failures, a race condition caused the system to incorrectly flag successful payments as failed. Consequently, 400 customers received erroneous notifications at 3:00 AM. The author argues that while automating repetitive labor is beneficial, it often inadvertently removes critical human judgment. The core lesson is to separate the automated 'labor'—such as data processing and drafting—from the 'irreversible steps' that impact the real world, like sending emails or executing payments. By keeping a human in the loop for final approval and requiring systems to display their 'blast radius' before execution, developers can maintain efficiency without sacrificing the safety net that human oversight provides. The author emphasizes that automation should act as an author, while humans remain the final skeptics.