minecraft-assets/data/minecraft/advancements/recipes/tools/lead.json

{
  "parent": "minecraft:recipes/root",
  "criteria": {
    "has_slime_ball": {
      "conditions": {
        "items": [
          {
            "items": [
              "minecraft:slime_ball"
            ]
          }
        ]
      },
      "trigger": "minecraft:inventory_changed"
    },
    "has_the_recipe": {
      "conditions": {
        "recipe": "minecraft:lead"
      },
      "trigger": "minecraft:recipe_unlocked"
    }
  },
  "requirements": [
    [
      "has_slime_ball",
      "has_the_recipe"
    ]
  ],
  "rewards": {
    "recipes": [
      "minecraft:lead"
    ]
  }
}