import type { Client, ClientCreateInput } from '../models/invoice.js';
import { Storage } from '../services/storage.js';
/**
 * Create a client or return the existing one if the email is already
 * known. This is an upsert-style operation so the tool is safe to call
 * repeatedly from agents — the description in index.ts promises this
 * contract and our callers rely on it (e.g. when ingesting bulk CSVs).
 */
export declare function createClient(input: ClientCreateInput, store?: Storage): Promise<Client>;