/**
 * Pieces shared by the per-engine limit collectors: JSON narrowing, the
 * window-name convention, and the registry-derived snapshot every collector
 * starts from. Split out of engine-limits.ts so each engine's collector can
 * live in its own module without duplicating them.
 */
import type { EngineLimitEngineSnapshot, JinnConfig } from "./types.js";
export type JsonRecord = Record<string, unknown>;
export declare function nowIso(): string;
export declare function isRecord(value: unknown): value is JsonRecord;
export declare function num(value: unknown): number | undefined;
export declare function str(value: unknown): string | undefined;
export declare function isoFromSeconds(seconds: number | undefined): string | undefined;
export declare function limitWindowName(fallback: string, durationMins: number | undefined): string;
export declare function baseSnapshot(config: JinnConfig, engine: string): EngineLimitEngineSnapshot;
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