/**
 * Snapshot intelligence helpers — structure-aware truncation for ARIA snapshots.
 *
 * ARIA snapshots use indentation-based YAML-like trees. Naive character-based
 * truncation can split in the middle of a node, making the output confusing.
 * These helpers preserve tree-node boundaries and provide metadata.
 */
/**
 * Truncate an ARIA snapshot at a line boundary, preserving complete tree nodes.
 *
 * Strategy:
 * 1. If the text is within `maxLength`, return as-is.
 * 2. Find the last newline before `maxLength`.
 * 3. Walk backwards to find a line at indentation level ≤ 2 (top-level nodes),
 *    ensuring we don't cut inside a deeply nested subtree.
 * 4. Append a truncation notice with stats.
 */
export declare function truncateSnapshotAtBoundary(text: string, maxLength: number): string;
/**
 * Produce a compact summary header for a snapshot.
 * Counts interactive elements (links, buttons, inputs) to help the agent
 * understand page complexity at a glance.
 */
export declare function snapshotSummaryHeader(snapshotText: string, pageUrl: string): string;