/**
 * Outbound file uploads via Slack's external upload flow.
 *
 * files.upload was retired on 2025-11-12; the replacement is the three-step
 * external flow: files.getUploadURLExternal per file, an HTTP POST of the raw
 * bytes to each returned upload_url, then a single files.completeUploadExternal
 * that shares all files to the destination as one message. The installed
 * @slack/web-api SDK wraps exactly this flow in `files.uploadV2` (and groups
 * files that share a destination into one completeUploadExternal call), so we
 * delegate to it rather than re-implementing the steps.
 */
import type { WebClient } from '@slack/web-api';
export interface UploadFileSpec {
    filePath: string;
    title?: string;
}
export declare function uploadFilesExternal(client: WebClient, files: UploadFileSpec[], dest: {
    channelId: string;
    threadTs?: string;
    initialComment?: string;
}): Promise<{
    sentFiles: number;
}>;