/**
 * @fileoverview Off-loads BLS observation mirror sync into a separate OS process.
 *
 * The observation harvest writes rows synchronously to SQLite (both `bun:sqlite`
 * and `better-sqlite3` are synchronous drivers). Running those writes on the
 * server's event loop blocks every concurrent tool call for the duration of the
 * page flush. This module spawns the sync in a child process via
 * `process.execPath`; WAL lets the server's reader connection keep serving
 * throughout. See issue #26.
 *
 * Dual role:
 *   - Imported by `src/index.ts` for {@link runObservationsSubprocess} — the
 *     parent spawn helper the in-process HTTP cron calls.
 *   - Run directly (`<runtime> dist/services/bls-observations/subprocess.js`)
 *     as the child entry point — the bottom guard runs one refresh and exits.
 *
 * @module services/bls-observations/subprocess
 */
import type { MirrorLogger } from '@cyanheads/mcp-ts-core/mirror';
/**
 * Spawn one mirror sync in a child process and resolve when it exits.
 * Never rejects — a failed harvest is logged and swallowed so a cron tick
 * can't crash the server. A no-op (with a warning) when a sync is already running.
 */
export declare function runObservationsSubprocess(opts: {
    timeoutMs?: number;
    log: MirrorLogger;
}): Promise<void>;
/** True when the subprocess module is currently running a sync (parent side). */
export declare function isObservationsSyncRunning(): boolean;
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