/** Tokens returned by a successful token-endpoint call. */
export interface TokenSet {
    /** Access token for authenticated API calls. */
    accessToken: string;
    /** Long-lived token used to mint new access tokens without re-auth. Absent if the flow did not return one. */
    refreshToken?: string;
    /** Absolute timestamp (ms since epoch) when the access token expires. */
    expiresAt: number;
    /** Space-delimited scopes the server actually granted, if reported. */
    grantedScope?: string;
}
/**
 * Reads a non-2xx response body and throws `TOKEN_EXCHANGE_FAILED`
 * with the OAuth `error` / `error_description` surfaced when present.
 */
export declare function throwTokenEndpointError(response: Response, context: string): Promise<never>;
/**
 * Parses a 2xx response from an RFC 6749 §5.1 token endpoint into a
 * `TokenSet`. `issuedAt` is the timestamp captured just before the
 * network call; the resulting `expiresAt` is conservative by ~RTT.
 */
export declare function parseTokenResponse(response: Response, issuedAt: number, endpointURL: string): Promise<TokenSet>;