The Automation Only One Person Understands Is a Time Bomb

There was a deployment pipeline at one job that everyone called "Tomasz's script." It did roughly nine critical things in a precise order, it had saved us thousands of hours over the years, and exactly one human on the planet understood how it worked. When Tomasz was around, this was invisible. When Tomasz went on holiday and the script failed at eleven at night, it stopped being a convenience and became the single scariest object in the company. We stood around a terminal reading code none of us had written, afraid to touch it and unable to leave it alone. This is the quiet paradox of automation. The whole point is to remove human effort, and it succeeds so completely that the humans forget how the thing works, or never learn in the first place. A manual process, for all its tedium, keeps knowledge distributed across everyone who performs it. A perfect automation concentrates that knowledge into whoever wrote it and then lets everyone else safely forget. The more indispensable the script becomes, the more dangerous its single point of understanding grows. What makes it worse is that these scripts accrete. They start simple and legible, then someone adds a special case for a weird environment, then a workaround for a vendor bug, then a hack to handle the one customer who is different. Each addition makes sense in the moment and makes the whole slightly more opaque. By the time it is truly load-bearing, it has become a small undocumented system that only its author can reason about, and its author is a busy person who is one job offer away from taking all of it with them. I have stopped treating a working automation as finished. Working is only half the requirement. The other half is that at least one other person can read it, understand what it does, and safely change it. That means the script explains its intent, not just its steps. It means the tribal knowledge lives somewhere other than one skull. It means occasionally, deliberately, having someone who did not wr