{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "#/components/schemas/InputMessage",
  "title": "InputMessage",
  "additionalProperties": false,
  "type": "object",
  "required": [
    "role",
    "content"
  ],
  "description": "A message in the conversation.",
  "properties": {
    "role": {
      "type": "string",
      "enum": [
        "user",
        "assistant"
      ],
      "description": "The role of the message author. System prompts are passed via the top-level `system` field, not as a message."
    },
    "content": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "array",
          "items": {
            "anyOf": [
              {
                "$ref": "#/components/schemas/TextBlock"
              },
              {
                "$ref": "#/components/schemas/ToolUseBlock"
              },
              {
                "$ref": "#/components/schemas/ToolResultBlock"
              }
            ]
          }
        }
      ],
      "description": "The message content. Pass a string for text-only messages or an array of content blocks for messages that include tool calls or tool results."
    }
  }
}