/**
 * Input multiplexer — merges harness-injected inputs (scheduler firings,
 * goal continuations) with the driver's own input source.
 *
 * Injected inputs are delivered ONLY at turn boundaries: the agent loop
 * calls getUserInput() between turns and queued items win the race there.
 * Nothing is ever pushed mid-turn — turn structure, permission prompts,
 * and prompt-cache behavior stay intact.
 *
 * The base input promise is held across calls: when the driver is parked
 * waiting for the user (interactive TUI, idle) and a scheduled prompt
 * arrives, the injected item is returned immediately while the pending
 * user input keeps waiting and is delivered at the next boundary. The
 * user's typing is never dropped.
 */
export interface InputMultiplexer {
    /** Drop-in replacement for the driver's getUserInput. */
    getUserInput: () => Promise<string | null>;
    /** Queue a synthetic input for the next turn boundary. */
    enqueue: (text: string, opts?: {
        priority?: boolean;
    }) => void;
    /** Number of injected inputs currently waiting. */
    pending: () => number;
}
export declare function createInputMultiplexer(base: () => Promise<string | null>): InputMultiplexer;