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, is not damageable or if the action does not ignore the game mode and this player is in creative mode.

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