/**
 * Inbound event dedupe (spec §7.1.4): chat platforms and the broker are both
 * at-least-once, so every ingress event id is checked against a TTL store
 * before any work detaches.
 */
/** Seen-key store consulted once per inbound event; hosts may inject their own. */
export interface DedupeStore {
    /** Returns true if key was already seen inside the TTL; records it otherwise. Atomic. */
    seen(key: string): boolean;
}
/** Options for {@link TtlDedupeStore}. */
export type TtlDedupeStoreOptions = {
    /** How long a key counts as seen. Default 600 000 (10 min). */
    ttlMs?: number;
    /** Clock override for tests. Default `Date.now`. */
    now?: () => number;
};
/**
 * In-memory {@link DedupeStore} with per-key TTL expiry.
 *
 * A hit does NOT refresh the key's expiry — only a miss records. Expired
 * entries are swept opportunistically; because keys are deleted before being
 * re-recorded, map insertion order stays expiry order and the sweep stops at
 * the first live entry (amortized O(1) per call).
 */
export declare class TtlDedupeStore implements DedupeStore {
    private readonly ttlMs;
    private readonly now;
    /** key → expiry timestamp (ms); insertion order == expiry order. */
    private readonly entries;
    constructor(opts?: TtlDedupeStoreOptions);
    seen(key: string): boolean;
    private sweep;
}
/** Options for {@link TtlCache}. */
export type TtlCacheOptions = {
    /** How long an entry stays retrievable after its last `set`. */
    ttlMs: number;
    /** Hard size backstop — oldest entries evict first once exceeded. */
    maxEntries: number;
    /** Clock override for tests. Default `Date.now`. */
    now?: () => number;
};
/**
 * Expiring, size-bounded string-keyed value cache — backs the engine's
 * egress-ref / reply-ref / delivered-content registries. Same sweep
 * discipline as {@link TtlDedupeStore}: delete-before-set keeps map insertion
 * order equal to expiry order, so every call physically prunes expired
 * entries from the front in amortized O(1).
 */
export declare class TtlCache<V> {
    private readonly ttlMs;
    private readonly maxEntries;
    private readonly now;
    /** key → value + expiry timestamp (ms); insertion order == expiry order. */
    private readonly entries;
    constructor(opts: TtlCacheOptions);
    /** Records `value` under `key`, refreshing its TTL; evicts oldest past `maxEntries`. */
    set(key: string, value: V): void;
    /** The live value under `key`, or undefined when absent or expired. */
    get(key: string): V | undefined;
    has(key: string): boolean;
    /** Physical entry count (post-sweep entries only shrink via set/get/has calls). */
    get size(): number;
    private sweep;
}
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