The Irons That Want No Key

As an action you can close the cuffs about the wrists of a creature that is willing, grappled, incapacitated, or restrained. A creature so bound cannot use its hands: it can take no action or Bonus Action requiring a free hand, it cannot cast a spell with a material component it must handle, and it has disadvantage on attack rolls and on ability checks that use the hands.

The cuffs cannot be picked, forced, filed, or struck off, nor opened by knock or by any magic that opens a lock, because there is no lock. They open, and fall, when a creature within earshot says aloud, correctly and in full, the offence for which the bound creature was taken up, or the debt for which it was arrested. The bound creature may say it itself. A wrong offence does nothing. So does an offence given in part, or in general terms, or in the words an officer would use in a warrant rather than the words of the thing that was done.

Nothing is provided for a creature bound without an offence. There are no words that open the irons upon such a creature, and the office that bound it must invent one and then say it, which two officers of this city have done.