import type { MutationItem } from '#blokkli/editor/types/state';
/**
 * A snapshot identifier for the mutation at a given history index. Used to
 * detect whether a previously snapshotted rollback target is still reachable —
 * the index alone is not enough because manual undo + new edits can replace
 * mutations in place while keeping the array length similar.
 */
export declare function computeHistorySignature(mutations: MutationItem[], index: number): string;
/**
 * Returns true when `index` still exists in `mutations` AND the mutation at
 * that position still matches the recorded `signature`. Used to decide
 * whether to show retry/edit on a user message.
 */
export declare function isHistorySnapshotReachable(mutations: MutationItem[], index: number | undefined, signature: string | undefined): boolean;