type: object
properties:
  content:
    type: string
    description: The content of the message
  content_type:
    type: string
    description: The type of message content
  parent_id:
    type: integer
    description: The ID of the parent message for threaded replies
  echo_id:
    type: string
    description: Client-generated ID for optimistic updates
  also_send_in_channel:
    type: boolean
    description: When sending a thread reply, also mirror it into the main channel view
  attachments:
    type: array
    description: File attachments to include with the message
    items:
      type: object
      properties:
        file:
          type: string
          format: binary
          description: The file to attach
        file_type:
          type: string
          enum:
            - image
            - audio
            - video
            - file
          description: The type of the attached file