/**
 * Pure transcript reducer (V2-050). Folds one `AnyAppEvent` into normalized
 * transcript state. Streaming deltas keep one open pending item per kind;
 * `assistant-message` / `thinking-block` finalize it. A real `tool-call`
 * discards any unfinalized assistant stream (raw tool-fence text). Event
 * order is preserved exactly as the model and tool runner emitted it.
 */
import type { AnyAppEvent } from "../../app/events/app-event.js";
import type { TranscriptState } from "./transcript-types.js";
export declare class TranscriptSequenceError extends Error {
    readonly expected: number;
    readonly received: number;
    constructor(expected: number, received: number);
}
export declare function applyAppEvent(state: TranscriptState, event: AnyAppEvent): TranscriptState;