Goethe wrote Der Zauberlehrling in 1797, a ballad of fourteen stanzas. Most people know it through the music Paul Dukas wrote a century later, and through Mickey Mouse carrying buckets in Fantasia.
The old master leaves the house. His apprentice is tired of fetching water, so he tries a spell he overheard and sets a broom to carry the buckets. It works. Soon the basin overflows and the floor floods, and the apprentice realizes he never learned the word that makes the broom stop. In a panic he splits it with an axe. Now two brooms are carrying water. The master comes home and ends it with one command.
Write the stop before the start
Every agent with permission to act needs its stopping word written before it runs: a hard limit on what it can spend and a way for a person to halt it halfway through a task.
In Breslau, a thought experiment on insuring AI agents, the meter holds any payment above the agent’s authority limit until a person releases it.
The axe deserves a second look. When the apprentice attacks the broom in a hurry, the problem doubles. Killing a misbehaving automation without understanding it often does the same, as retries fire and half-finished transactions sit in limbo waiting for someone to sort them out by hand.