/**
 * Outbound-fetch guard for the authorization server (#340).
 *
 * Anything the AS fetches because a client told it to (today nothing; the
 * Client ID Metadata Document behind a CIMD client_id when that lands) is a
 * server-side request forgery surface: a hostile client_id can point at the
 * Docker network, the cloud metadata service, or this very container. The
 * guard is three checks that all have to pass:
 *
 *   1. the URL itself: https only, no credentials, no literal private address;
 *   2. every address the hostname resolves to is public;
 *   3. the socket is pinned to the addresses that passed check 2, so a DNS
 *      answer that changes between resolve and connect (rebinding) cannot
 *      steer the connection somewhere private.
 *
 * The Coolify base URL is deliberately NOT routed through here. It is operator
 * configuration, and on a Coolify deployment it is an internal address by
 * design.
 */
import { type LookupFunction } from 'node:net';
export declare class UnsafeUrlError extends Error {
    constructor(message: string);
}
export interface ResolvedAddress {
    address: string;
    family: 4 | 6;
}
/** Resolves a hostname to every address it answers with. Injectable for tests. */
export type Resolver = (hostname: string) => Promise<ResolvedAddress[]>;
/** True for anything that is not a public unicast address (unparseable counts). */
export declare function isForbiddenAddress(address: string): boolean;
/**
 * Check 1: the URL as written. Throws UnsafeUrlError on anything that is not a
 * credential-free https URL to a non-local hostname or public literal address.
 */
export declare function assertPublicUrl(raw: string, options?: {
    allowInsecureHttp?: boolean;
}): URL;
/** Check 2: every address the name resolves to is public; returns them. */
export declare function resolvePublicAddresses(hostname: string, resolver?: Resolver): Promise<ResolvedAddress[]>;
/**
 * Check 3: a Node `lookup` that answers from the vetted list and never
 * consults DNS again, so the connection cannot be rebound after the check.
 */
export declare function pinnedLookup(addresses: ResolvedAddress[]): LookupFunction;
export interface FetchPublicJsonOptions {
    /** Hard deadline for the whole exchange. Claude allows 10 s for discovery. */
    timeoutMs?: number;
    /** Response size cap; a metadata document is a few hundred bytes. */
    maxBytes?: number;
    /** Development only (mirrors MCP_ALLOW_INSECURE_HTTP). */
    allowInsecureHttp?: boolean;
    resolver?: Resolver;
}
/**
 * GET a JSON document from a public URL with all three checks applied.
 * Redirects are not followed: a 3xx is a failure, because following one would
 * re-open every question the checks just answered.
 */
export declare function fetchPublicJson(raw: string, options?: FetchPublicJsonOptions): Promise<unknown>;