/**
 * Ensure the zk circuit resources are on disk before a proof runs. Idempotent
 * and concurrency-safe: the download runs at most once per process, and a
 * failed attempt clears the latch so a later proof can retry.
 *
 * Resolves silently when the resources are already present (the warm npx cache,
 * or after a manual `npm run download:zk-files`) and when
 * `@reclaimprotocol/zk-symmetric-crypto` isn't installed at all (SDK-only
 * consumers have nothing to prove).
 *
 * All output goes to stderr (fd 2): the MCP server speaks JSON-RPC over stdout,
 * so a stray write to fd 1 mid-session would corrupt the protocol.
 */
export declare function ensureZkFiles(): Promise<void>;