Frontend representation of a message in the conversation, with structured parts for rich rendering.

Includes a parts array for granular rendering of tool calls, reasoning blocks, and images. The metadata field allows attaching arbitrary data for custom rendering.

Related: MessagePart defines part types, messagesAtom stores the array, MessageBubble renders individual messages.

interface AgentMessage {
    id: string;
    role: 'user' | 'assistant' | 'system' | 'tool';
    content: string;
    createdAt: Date;
    agentId?: string;
    metadata?: Record<string, unknown>;
    parts?: MessagePart[];
}