Sarah entrusts her spy will to Chuck
Sarah's Spy Will was made in anticipation of her possible death in the field.
A spy will in the Chuck universe is sometimes contained in a small circular safe, opened by a cypto key, or possibly, as with Sarah, on a computer storage device. The spy will is often entrusted to the spy's family, friends, or loved ones to be opened in the event of the agent's death.
Sarah gives her spy will to Chuck, since she says that he is her new life. It is believed that Chuck is still in possession of this will. Sarah giving Chuck her will, prompted him to make one of his own.