export interface BrokerStartupFailureMarker {
    version: 1;
    reason: string;
    exitCode: number | null;
    signal: string | null;
    writtenAt: number;
    /**
     * pid of the exact broker process that wrote this marker. `ensureBroker`
     * only trusts a marker whose pid matches the exact spawned child it just
     * reaped -- a marker left behind by a stale or foreign broker process (for
     * example a losing racer from a concurrent spawn, or a marker predating the
     * pre-spawn clear) must never be misattributed to a different spawn's
     * failure.
     */
    pid: number;
}
export declare function brokerStartupFailurePath(agentDir: string): string;
/**
 * Best-effort durable marker write; never throws (diagnostics must not mask the
 * exit itself). `pid` must be the writing broker process's own pid
 * (`process.pid`) so a later reader can bind the marker to the exact spawned
 * child it is attributing the failure to.
 */
export declare function writeBrokerStartupFailureMarker(agentDir: string, failure: {
    reason: string;
    exitCode: number | null;
    signal: string | null;
    pid: number;
}): Promise<void>;
/** Reads a bounded startup-failure marker; `undefined` when absent or malformed. */
export declare function readBrokerStartupFailureMarker(agentDir: string): Promise<BrokerStartupFailureMarker | undefined>;
/** Best-effort marker removal; used at spawn so a stale marker never misattributes an older failure. */
export declare function clearBrokerStartupFailureMarker(agentDir: string): Promise<void>;
/** Typed error returned when a detached broker exits before discovery. */
export declare class BrokerStartupError extends Error {
    readonly code = "broker_startup_failed";
    readonly exitCode: number | null;
    readonly signal: string | null;
    readonly reason: string;
    readonly stderrExcerpt?: string;
    constructor(fields: {
        exitCode: number | null;
        signal: string | null;
        reason: string;
        stderrExcerpt?: string;
    });
}