import type { Api, Model } from '@earendil-works/pi-ai';
import type { PromptCachePolicy } from './prompt-cache-plan.js';
export declare function resolvePromptCacheTtlMs(model: Model<Api>, policy: PromptCachePolicy): number;
export declare function recordPromptCacheTouch(sessionKey: string, model: Model<Api>, usage: {
    cacheRead?: number;
    cacheWrite?: number;
}, now?: number): void;
export declare function isPromptCacheExpired(sessionKey: string, model: Model<Api>, policy: PromptCachePolicy, now?: number): boolean;
export declare function clearPromptCacheTouches(): void;