type TransportEvent = | { type: 'message-start'; messageId: string; agentId: string }
  | { type: 'text-delta'; messageId: string; delta: string }
  | { type: 'text-complete'; messageId: string; content: string }
  | { type: 'tool-call-start'; toolCallId: string; toolName: string; agentId: string }
  | { type: 'tool-call-args'; toolCallId: string; args: unknown }
  | { type: 'tool-call-result'; toolCallId: string; result: unknown }
  | { type: 'tool-call-error'; toolCallId: string; error: string }
  | { type: 'reasoning-delta'; messageId: string; delta: string }
  | { type: 'agent-handoff'; fromAgent: string; toAgent: string; reason: string }
  | {
      type: 'approval-required';
      toolCallId: string;
      toolName: string;
      args: unknown;
      agentId: string;
    }
  | { type: 'stream-complete'; conversationId: string }
  | { type: 'error'; error: string; code?: string }