@type t() ::
  {:user_message_chunk, ACP.ContentChunk.t()}
  | {:agent_message_chunk, ACP.ContentChunk.t()}
  | {:agent_thought_chunk, ACP.ContentChunk.t()}
  | {:tool_call, ACP.ToolCall.t()}
  | {:tool_call_update, ACP.ToolCallUpdate.t()}
  | {:plan, ACP.Plan.t()}
  | {:available_commands_update, ACP.AvailableCommandsUpdate.t()}
  | {:current_mode_update, ACP.CurrentModeUpdate.t()}
  | {:config_option_update, ACP.ConfigOptionUpdate.t()}
  | {:session_info_update, ACP.SessionInfoUpdate.t()}