It should go without saying, but you do not cut music wire with diagonal cutters intended for electrical wire or the low-carbon steel shears built into wire strippers. I use a bicycle cable cutter that easily slices through the hard wire used in brake cables and their housing:
I’ve owned this one forever, but those cutters from Park should work just as well; the odd protrusions behind the pivot crimp aluminum caps on stranded cable. I also have diagonal cutters with hardened jaws, but they’re too bulky for fine work and tend to fire the stub ends across the Basement Laboratory.
Every now and again I touch up the jaws with a diamond file to get rid of small dings; despite being hardened, those fine points seem particularly prone to burrs.
When you see an ordinary wire cutter with matching half-moons in each blade, you know what happened…