N.Y. C.P.L.R. 2104

Rule 2104. Stipulations. An agreement between parties or their\nattorneys relating to any matter in an action, other than one made\nbetween counsel in open court, is not binding upon a party unless it is\nin a writing subscribed by him or his attorney or reduced to the form of\nan order and entered. With respect to stipulations of settlement and\nnotwithstanding the form of the stipulation of settlement, the terms of\nsuch stipulation shall be filed by the defendant with the county clerk.\n