Interface EnhancedMessage

interface EnhancedMessage {
    id: string;
    role: "user" | "assistant" | "system" | "tool";
    content: string;
    createdAt?: Date;
    metadata?: {
        model?: string;
        tokens?: { input: number; output: number; total: number };
        cost?: number;
        responseTime?: number;
        reasoning?: {
            steps: { type: string; content: string; confidence?: number }[];
        };
        sources?: {
            id: string;
            title: string;
            url?: string;
            content: string;
            relevance?: number;
        }[];
    };
    data?: any;
    toolInvocations?: {
        toolCallId: string;
        toolName: string;
        args: any;
        result?: any;
        state: "partial"
        | "complete"
        | "error";
    }[];
}