Interface UsageEvent

interface UsageEvent {
    cachedReadTokens?: number;
    cachedTokens: number;
    cachedWriteTokens?: number;
    cost: string;
    costUSD: number;
    inputTokens: number;
    outputTokens: number;
    botId?: string;
    durationMs: number;
    finishReason: CanonicalFinishReason;
    model: string;
    provider: CanonicalProvider;
    routingDecision?: string;
    sessionId?: string;
    tenantId?: string;
    timestamp: string;
}