/**
 * "A newer clustly is on npm" — the update-notifier pattern. The notice is printed from a
 * cache BEFORE the command runs (commands process.exit() directly, so "after" is unreliable),
 * and the cache is refreshed by a fire-and-forget registry fetch at most once a day. Source
 * of truth is the npm `latest` dist-tag, never the app's CURRENT_SDK_VERSION: the app can be
 * ahead of npm (2026-09-02: package.json said 0.7.0 for three days while npm served 0.6.1),
 * and a nudge toward an unpublished version is a 404 for the user.
 *
 * Best-effort by design: every fs/fetch/JSON failure is swallowed. This must never cost a
 * command latency or break it.
 */
export interface UpdateCheckDeps {
    now: () => number;
    home: string;
    /** A plain string map, not the ambient `NodeJS.ProcessEnv`: a caller passing a
     *  one-key literal (`{ CI: "true" }`) should not have to cast. */
    env: Record<string, string | undefined>;
    /** Resolve the registry's `latest` version; null on any failure. */
    fetchLatest: () => Promise<string | null>;
    notify: (line: string) => void;
}
/** True iff both are stable x.y.z and candidate > current, numerically per component. */
export declare function isNewer(candidate: string, current: string): boolean;
/**
 * Print the notice if the cache says a newer stable exists; kick a background refresh if the
 * cache is stale. Returns the refresh promise (tests await it; the CLI does not).
 */
export declare function maybeNotifyUpdate(current: string, deps?: Partial<UpdateCheckDeps>): Promise<void>;