/**
 * G6.4 / RL-16 — heartbeat truncation helper.
 *
 * Each dispatch record keeps an append-only `heartbeats[]` array so
 * reducers / auditors can reconstruct what the sub-agent did. Without
 * a cap, a long-running sub-agent can blow the record JSON past 1 MB
 * (a 30s cadence over a 1-hour run = 120 entries * ~120 bytes = ~14 KB;
 * a 5s cadence over 24h = 17 000 entries * ~120 bytes = ~2 MB). The
 * 100-entry cap is LLM-friendly: stale heartbeats are not informative
 * once the poller has read them, so dropping the oldest ones is a
 * non-event.
 *
 * Pure helper; no IO. The writer in `dispatch-record-writer.ts` calls
 * this on every `appendHeartbeat`. Exposed as a separate module so
 * tests can pin the contract.
 */
import type { Heartbeat } from './dispatch-record-writer.js';
export declare const HEARTBEAT_TRUNCATE_LIMIT = 100;
export interface TruncationResult {
    readonly heartbeats: readonly Heartbeat[];
    readonly truncated: boolean;
    /** The number of entries dropped by this truncation. */
    readonly dropped: number;
}
/** Apply the 100-entry cap. Returns the most recent N entries + a flag. */
export declare function truncateHeartbeats(entries: readonly Heartbeat[]): TruncationResult;