/**
 * Tracks in-flight background tasks (run_in_background Bash/Agent) for a single
 * persistent Claude session, by observing the CLI's stream-json `system` events.
 *
 * Observed lifecycle (real shapes, see /tmp/bg-capture.mjs):
 *   - launch:     { type:'system', subtype:'task_started',      task_id, task_type }
 *   - work done:  { type:'system', subtype:'task_updated',      task_id, patch:{status:'completed'|'failed'|'killed'} }
 *   - delivery:   { type:'system', subtype:'task_notification', task_id, status:'completed', summary }
 *
 * task_notification is the event that actually re-invokes the model (the spontaneous
 * continuation turn). BUT — 2026-07-10 investigation — the CLI does NOT always emit it:
 *   - CC versions ≤ 2026-07-05: a task completing while its owning turn was still active got
 *     task_updated{completed} and NEVER a notification (11 verified cases; sessions lived
 *     20+ min after, incl. further turns, with zero notifications). Fixed in CC ≥ 07-06,
 *     but the contract cannot be trusted across CLI auto-updates.
 *   - TaskStop-killed tasks (patch.status 'killed') never get a notification at all.
 *
 * The tracker therefore keeps TWO sets:
 *   - `running`     — started, work not yet finished. Snapshot as pendingBackgroundTasks.
 *   - `undelivered` — work finished (task_updated terminal status) but the notification has
 *     not been observed. The CLI may deliver it up to ~24s later (observed gap with several
 *     parallel tasks) — or never. Snapshot as undeliveredBackgroundTasks; orchestration arms
 *     a grace watchdog (bg-wait-guard) for these instead of waiting forever.
 * Killed tasks are dropped from both sets immediately (no notification will ever come).
 */
export declare class BgTaskTracker {
    private readonly running;
    private readonly undelivered;
    /** Set when a background task completes; the spontaneous continuation turn that
     *  follows is recognized via this flag. Cleared by disarmContinuation(). */
    continuationArmed: boolean;
    /** Observe one parsed stream-json event. Idempotent per task_id. */
    observe(data: any): void;
    /** Tasks whose work is still executing. */
    get pendingCount(): number;
    /** Tasks whose work finished but whose task_notification has not been observed. */
    get undeliveredCount(): number;
    /** True while anything may still produce a continuation — the session must stay alive. */
    hasPending(): boolean;
    disarmContinuation(): void;
}
/** A `result` event produced by a background-task continuation turn carries
 *  origin.kind === 'task-notification'. Used to distinguish a spontaneous
 *  continuation result from a normal turn result. */
export declare function isContinuationResult(data: any): boolean;
/** How a parsed stream-json line should be routed by the session's handleLine. */
export type LineRoute = 'normal' | 'open-continuation' | 'ignore';
/**
 * Decide how a parsed line should be routed given whether a turn is currently active.
 * Pure: depends only on the tracker's armed state and the event type.
 */
export declare function routeLine(tracker: BgTaskTracker, data: any, hasActiveTurn: boolean): LineRoute;