Cyphers requerem um ataque, geralmente Int-based (com algumas exceções).
Do Corebook Numenera, p84:
Each character gets one turn each round. On a character’s turn, she can do one thing—an action. All actions fall into one of three categories: Might, Speed, or Intellect (just like the three stats). Many actions require die rolls—rolling a d20.
Every action performs a task, and every task has a difficulty that determines what number a character must reach or surpass with a die roll to succeed. Most tasks have a difficulty of 0, which means the character succeeds automatically. ... Actions that are usually difficult or that become difficult due to the situation (such as shooting at a target in a blizzard) have a higher difficulty. These actions usually require a roll.
Do Corebook Numenera, p280 ( ênfase minha ):
If a character uses a cypher, the action to use it is Intellect based unless otherwise described or logic suggests otherwise. For example, throwing a detonation might be Speed based because the device is physical and not really technical, but using a ray emitter is Intellect based.
Assim, toda ação requer um teste, a menos que seja claramente trivial. Cyphers exigem um teste de Int, a menos que Might ou Speed façam mais sentido.