OutputItemAddedEvent

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "#/components/schemas/OutputItemAddedEvent",
  "title": "OutputItemAddedEvent",
  "description": "Output item added event (type: \"response.output_item.added\").\nEmitted when a new output item (message or tool call) starts.\n",
  "properties": {
    "item": {
      "$ref": "#/components/schemas/OutputItem"
    },
    "output_index": {
      "format": "int64",
      "type": "integer"
    },
    "sequence_number": {
      "description": "Monotonically increasing sequence number for event ordering",
      "format": "int64",
      "type": "integer"
    },
    "type": {
      "$ref": "#/components/schemas/EventType"
    }
  },
  "required": [
    "type",
    "sequence_number",
    "item",
    "output_index"
  ],
  "type": "object"
}