Are anti-short bushings required by code for MC cable?
For standard interlocked armor MC cable, no. Article 330 of NEC 2023 has no requirement for an anti-short bushing at MC terminations, and listed MC connectors are tested and listed for use without them. The rule people are remembering belongs to AC cable: 320.40 requires an insulating bushing between the conductors and the armor at every AC termination, which is why the red heads come in the bag.
Why the two cables differ
AC cable relies on its armor plus an internal bond strip as the equipment grounding path, and its conductors are only paper-wrapped, so the sharp cut edge of the armor sits directly against thermoplastic insulation. MC cable carries a full-size insulated green ground and each conductor is wrapped in a mylar assembly tape, so the listing agencies concluded the cut edge is not the same hazard when a listed connector is properly installed.
When the bushing becomes mandatory anyway
110.3(B) makes manufacturer instructions enforceable. Some MC cable and some connectors ship with instructions calling for the bushing, and MC-AP or special constructions can require them per their listing. If the bag of red heads comes with the cable and the instruction sheet says to use them, an inspector can hold you to it. Health care facility MC with a redundant ground path also deserves a close read of its instructions.
What inspectors actually do
Plenty of AHJs want to see anti-shorts on every armored cable, MC included, and arguing the article number on a ladder is a losing trade. The bushings are free with the cable, take one second each, and visibly protect the insulation while the cable gets twisted into the connector. Many crews standardize on them for that reason alone.
Field notes
Whatever you do about the bushing, make the cut clean. A proper rotary MC cutter that scores one armor rib leaves a safe edge; dikes and a hacksaw leave the burrs that cause the shorts the bushing is named after. Strip length, a straight conductor entry, and a snug listed connector matter more than the red plastic.