/**
 * Thrown when a feature-branch host never becomes ready.
 *
 * Root cause (GLU-2631): feature-branch login had no shared error whose
 * message is exactly "host never became ready", and no gate on a non-empty
 * `NX_FEATURE_BRANCH_BASE_URL`. A host that never served `/env` or a stuck
 * session handoff therefore failed as a page error. Later phases import this
 * error and {@link isFeatureBranchHost}.
 */
export declare class HostNeverBecameReadyError extends Error {
    /** Creates an error whose message is exactly "host never became ready". The wait that ended is kept as `cause`. */
    constructor(cause?: unknown);
}
/**
 * True only when `NX_FEATURE_BRANCH_BASE_URL` is a non-empty string.
 *
 * Unset or `""` leaves the gate off. Staging and production do not set the variable.
 */
export declare const isFeatureBranchHost: () => boolean;