import type { RunnerEvent } from "./sync-runner.js";
export interface RunnerEventStreams {
    stdout: {
        write: (chunk: string) => boolean | void;
    };
    stderr: {
        write: (chunk: string) => boolean | void;
    };
}
export declare function setRunnerEmitObserver(observer: (() => void) | null): void;
/**
 * Fire the installed observer once, swallowing any fault. Call this at
 * work-driven seams that do NOT route a protocol event — notably the engine's
 * raw heartbeat, which is called far more often than the rate-limited heartbeat
 * EVENT — so the governor keeps observing during an async-heavy pass that emits
 * few events. The observer (the heap checkpoint) is itself gated, so calling it
 * often is cheap.
 */
export declare function notifyRunnerEmitObserver(): void;
export declare function routeEvents(event: RunnerEvent, streams: RunnerEventStreams): void;
export declare function createRunnerEmitter(streams: RunnerEventStreams): (event: RunnerEvent) => void;
/**
 * Emit a CLASSIFIED `error` event for a top-level uncaught runner rejection,
 * BEFORE the process exits non-zero.
 *
 * The menubar (hq-sync) treats a non-zero runner exit with NO error event seen
 * at all as an "unexplained crash" and ALWAYS alerts on it. That is correct for
 * a real panic/OOM, but the historical top-level catch wrote only a plain
 * stderr line (not a protocol event) for EVERY uncaught rejection — so even a
 * benign cause that bubbled to the top (transient network blip, a
 * not-yet-provisioned 404, an expected ACL-scope skip) drove a false alert
 * (HQ-SYNC-WEB-6). Emitting a structured `{type:"error"}` event here routes the
 * failure through the menubar's `is_alertable_error` classifier, so the benign
 * cases are suppressed while genuine defects still surface.
 *
 * Best-effort: if routing itself throws, fall back to a plain stderr line so the
 * failure is never fully silent in the logs.
 */
export declare function emitUncaughtRunnerError(err: unknown, streams: RunnerEventStreams): void;
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