In order to violate the Sabbath, one must commit a complete act of labor. The Mishnah gives some examples of what constitutes a full measure of forbidden work.

12-1 One who builds [on the Sabbath], how much must he build in order to be liable? Whoever builds anything at all, or hews stone at all, or strikes with a hammer or an adze, or bores a hole at all, is liable. This is the general rule: Whoever commits an act of (forbidden) labor on the Sabbath, and his work will last, is liable.

Rabban Simeon ben Gamliel said: “Even if one just struck a hammer on the anvil during the work, he is liable since he is like one who prepares for (forbidden) labor.”

12-2 Whoever ploughs at all, or weeds at all, or cuts off dead leaves or prunes at all, is liable. Whoever gathers wood, if it is to set it in order, is liable for any amount at all. If it is to burn, he is liable for an amount sufficient to cook the smallest egg. Whoever gathers herbs, if it is to set the field in order, is liable for any amount at all. If it is to feed cattle, he is liable for an amount sufficient to fill a kid’s mouth.

12-3 Whoever writes two letters, whether with his right or left hand, whether the same or different letters, whether in different inks, or in any language, is liable….

61. Trans. S. Berrin.