/**
 * On-disk TTL cache (SPEC §2). Entries live under ~/.cache/gaff-check/,
 * keyed by a hash of source + params. Each source declares its own TTL.
 * `--no-cache` disables reads and writes (useful in dev / e2e).
 */
/** Per-source TTLs in milliseconds (SPEC §2). */
export declare const TTL: {
    readonly nominatim: number;
    readonly planning: number;
    readonly ppr: number;
    readonly radon: number;
    readonly zoning: number;
    readonly flood: number;
    readonly cso_ber: number;
    readonly garda_crime: number;
    readonly cso_crime: number;
};
export type SourceName = keyof typeof TTL;
export declare function setCacheEnabled(on: boolean): void;
/** Override the cache directory (tests only). */
export declare function setCacheDir(dir: string): void;
/**
 * Return the cached value for (source, params) if fresh, otherwise call
 * `fetcher`, store the result, and return it. Cache failures never fail
 * the request — they degrade to a live fetch.
 */
export declare function cached<T>(source: SourceName, params: unknown, fetcher: () => Promise<T>): Promise<T>;