A cutting insert for a tool for machining a workpiece. The cutting insert comprises a clamping section which comprises a coolant channel which is configured as a through-hole. Further, the cutting insert comprises a cutting head having at least one cutting member which comprises a main cutting edge, a rake face which adjoins the main cutting edge, and a chip-breaking geometry which protrudes from the rake face or which is introduced into the rake face and which is configured to break a chip which is machined with the main cutting edge. Furthermore, the cutting insert comprises a cantilever arm which connects the clamping section to the cutting head and which has a smaller diameter than the clamping section. A portion of the cutting head comprising the chip-breaking geometry at least partially covers the coolant channel when viewed in a plan view from a front side along a longitudinal axis of the cutting insert.