How to work with a custom damage type

I want to create a custom damage type so I can mess around with it. I've tried using misode and I got this : 
  "message_id": "Touched Grass",
  "exhaustion": 0.1,
  "scaling": "never",
  "effects": "hurt",
  "death_message_type": "default"
}
      ```
But it doesn't get detected when I try to call for it. File name is grasss.json and in damage_type folder under namespace. What am I doing wrong? (Probably something dumb, but can't figure it out)