/**
 * Epoch watcher for lane-bound sessions: the prompt-awareness half of "perfect sync". Watches
 * the shared `epoch.json` (fs.watch on its directory -- the file is replaced by rename) and, on
 * an epoch advance by ANOTHER lane, injects one deterministic staleness notice through the host's
 * message seam. Enforcement never rides on this watcher -- the lane gate (G8) and the land CAS
 * (G3) fail closed even if it dies; this only makes lanes learn promptly instead of at their
 * next tool call.
 */
import type { WorktreeSyncEpoch } from "./codes.ts";
export interface EpochWatcherConfig {
    epochFile: string;
    /** The lane this session is bound to: lands BY this lane never notify it. */
    laneKey: string;
    notify: (text: string) => void;
    /** Debounce for rename/change event bursts. */
    debounceMs?: number;
}
export interface EpochWatcherHandle {
    stop(): void;
}
/** Deterministic notice text -- assembled from epoch facts, never model-generated. */
export declare function formatEpochNotice(epoch: WorktreeSyncEpoch, laneKey: string): string;
/**
 * Start watching. The initial epoch is read once as the baseline; only ADVANCES past it notify
 * (a fresh session never gets a notice for history). fs.watch is backed by a low-frequency
 * poll re-read on each event burst only -- no timers run while the store is quiet.
 */
export declare function startEpochWatcher(config: EpochWatcherConfig): EpochWatcherHandle;
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