/**
 * Returns error messages describing any duplicate `block_id` values across the
 * given blocks array. Pairs with the JSON Schema (draft 2020-12) in this
 * package — JSON Schema can't express per-property uniqueness across items, so
 * this check sits alongside structural validation.
 *
 * Skips `markdown` blocks: Slack drops their `block_id` on send ("The block_id
 * is ignored in markdown blocks and will not be retained" per docs), so
 * duplicates involving markdown blocks are false positives from Slack's POV.
 * @param blocks - array of Block Kit blocks (or anything with an optional `block_id`)
 * @returns array of human-readable error messages (empty when no duplicates)
 */
export declare function findDuplicateBlockIds(blocks: readonly {
    type?: string;
    block_id?: string;
}[]): string[];
//# sourceMappingURL=find-duplicate-block-ids.d.ts.map