import { type Eip155CaipChainId } from "./caip";
/**
 * Validate a candidate chain config by issuing a single `eth_chainId`
 * JSON-RPC POST and comparing the response to the numeric reference of
 * `candidate.caip2`. Stateless utility — consumers call this before
 * persisting a custom-chain entry so validation rules don't fragment.
 */
export declare function validateChainConfig(candidate: {
    caip2: Eip155CaipChainId;
    rpcUrl: string;
}, fetchImpl?: typeof fetch): Promise<{
    ok: true;
} | {
    ok: false;
    reason: string;
}>;