ChatMessage

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "ChatMessage",
  "type": "object",
  "description": "A single message in a chat conversation.",
  "properties": {
    "role": {
      "type": "string",
      "description": "Role of the message author.",
      "enum": [
        "system",
        "user",
        "assistant"
      ],
      "example": "user"
    },
    "content": {
      "type": "string",
      "description": "Content of the message.",
      "example": "Hello, how are you?"
    }
  },
  "required": [
    "role",
    "content"
  ]
}