If you mean a Leatherman multitool, you won't have a problem wearing one in NYC. Many people, including me(Leatherman Supertool), wear one every day on their belts. Usually for some type of work...construction, electrical, etc. The NYC carry laws on knives(to the best of my knowledge) are:
-Blade length under 4"
-No switchblades/automatics
-No balisongs
-No double edged blades
-No gravity knives
-No knives with knuckle guards