A medical instrument, comprising: an elongated channel configured to support a staple cartridge, the staple cartridge comprising a plurality of staples; an anvil mechanically coupled to the elongated channel, wherein the anvil comprises an exterior surface extending between a proximal end and a distal end, wherein the exterior surface comprises a tissue-contacting surface and a plurality of staple-forming pockets; at least one electrical circuit at least partially positioned on the exterior surface of the anvil, wherein the at least one electrical circuit comprises one or more electrically conductive circuit elements positioned on the tissue-contacting surface and outside of the plurality of staple-forming pockets, wherein portions of the electric circuit other than the one or more electrically conductive circuit elements are: armored with a protective outer layer; positioned below the tissue-contacting surface of the anvil; or positioned in thin channels that are thinner than a staple leg; and the one or more electrically conductive circuit elements are none of: armored with a protective outer layer; positioned below the tissue-contacting surface of the anvil; and positioned in thin channels that are thinner than a staple leg; an indicator system comprising at least one indicator; and a logic circuit electrically in electrical communication with the at least one electrical circuit and the indicator system, wherein the logic circuit is configured to activate the at least one indicator when the one or more electrically conductive circuit elements are severed by a staple leg and an electrical continuity of the at least one electrical circuit is interrupted. an elongated channel configured to support a staple cartridge, the staple cartridge comprising a plurality of staples; an anvil mechanically coupled to the elongated channel, wherein the anvil comprises an exterior surface extending between a proximal end and a distal end, wherein the exterior surface comprises a tissue-contacting surface and a plurality of staple-forming pockets; at least one electrical circuit at least partially positioned on the exterior surface of the anvil, wherein the at least one electrical circuit comprises one or more electrically conductive circuit elements positioned on the tissue-contacting surface and outside of the plurality of staple-forming pockets, wherein portions of the electric circuit other than the one or more electrically conductive circuit elements are: armored with a protective outer layer; positioned below the tissue-contacting surface of the anvil; or positioned in thin channels that are thinner than a staple leg; and the one or more electrically conductive circuit elements are none of: armored with a protective outer layer; positioned below the tissue-contacting surface of the anvil; and positioned in thin channels that are thinner than a staple leg; armored with a protective outer layer; positioned below the tissue-contacting surface of the anvil; or positioned in thin channels that are thinner than a staple leg; armored with a protective outer layer; positioned below the tissue-contacting surface of the anvil; and positioned in thin channels that are thinner than a staple leg; an indicator system comprising at least one indicator; and a logic circuit electrically in electrical communication with the at least one electrical circuit and the indicator system, wherein the logic circuit is configured to activate the at least one indicator when the one or more electrically conductive circuit elements are severed by a staple leg and an electrical continuity of the at least one electrical circuit is interrupted.