The minecraft:damage_item action damages the item stack in the context by the amount given. Note that this is different from the minecraft:set_damage item modifier, as this actually breaks the item stack once fully damaged and takes into account preserved items and the Unbreaking enchantment. It also calls the minecraft:item_durability_changed advancement trigger. This action is unsuccessful if the item stack is empty or is not damageable.

{
  "type": "minecraft:damage_item",
  "amount": 1
}