/**
 * Where the HTTP transport listens, and whether it is allowed to start at all.
 *
 * The hole this closes: with GTM_MCP_TRANSPORT=http and neither Stytch nor
 * GTM_MCP_HTTP_AUTH_TOKEN configured, the bearer check was skipped entirely
 * (it lived inside `if (staticToken)`), and `app.listen(port)` with no host
 * binds every interface. So the server handed its own Google credentials -
 * full GTM and GA4 access, writes included when those flags are on - to anyone
 * who could reach the port. The only guard was one console warning, and the
 * startup banner said "running on http://localhost:PORT", which reinforced
 * exactly the wrong belief about reachability.
 *
 * Everything else in this codebase is fail-closed (`=== 'true'` on every flag,
 * confirm on every write, deletes behind their own gate). This brings the HTTP
 * transport in line.
 *
 * PURE, so the matrix is unit-testable without binding a socket.
 */
export type AuthMode = 'stytch' | 'static-token' | 'none';
export interface HttpBinding {
    /** Interface to bind. */
    host: string;
    authMode: AuthMode;
    /** Set when the server must NOT start; the string is the operator-facing reason. */
    refuse?: string;
    /** Set when the configuration is allowed but worth saying out loud. */
    warning?: string;
}
/** Loopback covers IPv4; Node also accepts ::1 but 127.0.0.1 is the safer default to print. */
export declare const LOOPBACK = "127.0.0.1";
export declare const ALL_INTERFACES = "0.0.0.0";
/**
 * Decide the bind host and whether to start.
 *
 * The rules, in the order they matter:
 *
 *  1. AUTHENTICATED servers are unchanged. Stytch or a static token means the
 *     hosted multi-user deployment, which legitimately listens on every
 *     interface - so the default stays ALL_INTERFACES and existing deployments
 *     keep working. Making them loopback-only would have broken every hosted
 *     install to fix a hole that only exists without auth.
 *
 *  2. UNAUTHENTICATED servers refuse to start. Not a warning: a warning on
 *     stderr competes with retry logs and gets missed, and the failure mode is
 *     handing an operator's advertising and analytics accounts to the network.
 *     GTM_MCP_HTTP_ALLOW_UNAUTHENTICATED=true is the deliberate opt-in, matching
 *     the `=== 'true'` idiom used by every other gate here.
 *
 *  3. An unauthenticated server that IS allowed binds LOOPBACK by default, so
 *     the opt-in covers local development without also publishing the port.
 *     Reaching the network from there takes a second explicit step.
 */
export declare function resolveHttpBinding(env?: NodeJS.ProcessEnv): HttpBinding;
/** What to print at startup: the host actually bound, never a hardcoded "localhost". */
export declare function bindingBanner(b: HttpBinding, port: number): string;
//# sourceMappingURL=httpBinding.d.ts.map