/**
 * Dependency-free update notifier for the agentled CLI.
 *
 * Checks the npm registry for a newer version of the given package and
 * prints a one-line notice to stderr before the process exits. Design
 * constraints:
 *   - Zero external dependencies (uses Node 18+ `fetch`).
 *   - Silent on failure — a missing network, registry hiccup, or malformed
 *     cache must never break the user's command.
 *   - Cached: one HTTP round-trip per 24h (cache miss adds ≤1.2s latency),
 *     cache hits are free.
 *   - Opt-out: honors `AGENTLED_NO_UPDATE_CHECK=1`, `NO_UPDATE_NOTIFIER=1`,
 *     and standard CI env vars. Also skips when stderr is not a TTY.
 */
export declare const DEFAULT_TTL_MS: number;
export declare const DEFAULT_TIMEOUT_MS = 1200;
export interface CacheEntry {
    checked: number;
    latest: string;
}
export declare function cachePath(pkgName: string): string;
export declare function readCache(pkgName: string): CacheEntry | null;
export declare function writeCache(pkgName: string, entry: CacheEntry): void;
export declare function isDisabled(): boolean;
export declare function semverCompare(a: string, b: string): number;
export declare function fetchLatestVersion(pkgName: string, timeoutMs: number): Promise<string | null>;
export interface CheckOptions {
    ttlMs?: number;
    timeoutMs?: number;
    fetcher?: (pkg: string, timeoutMs: number) => Promise<string | null>;
}
export declare function checkForUpdate(pkgName: string, currentVersion: string, opts?: CheckOptions): Promise<string | null>;
export declare function renderUpdateNotice(pkgName: string, current: string, latest: string): string;
export declare function printUpdateNotice(pkgName: string, current: string, latest: string): void;