import type { Ref } from 'vue';
export declare function useConversationUsage(conversationId: Ref<string | null | undefined>): {
    usageData: any;
    billing: any;
    loading: any;
    error: any;
    cacheInsight: any;
    costBreakdown: any;
    modelRows: any;
    costBarSegments: any;
    formatBillingCost: (cost: number) => string;
    fetchUsage: () => Promise<void>;
};