export interface UpstreamTool {
    name: string;
    description?: string;
    inputSchema?: unknown;
}
export interface UpstreamOptions {
    command: string;
    args: string[];
    env?: Record<string, string>;
}
/**
 * Thin wrapper around an upstream MCP server (Playwright MCP by default).
 * Spawns the subprocess via the SDK's StdioClientTransport, initialises a
 * client session, and exposes list/call.
 */
export declare class UpstreamSession {
    private client;
    private transport;
    private tools;
    start(opts: UpstreamOptions): Promise<UpstreamTool[]>;
    getTools(): UpstreamTool[];
    callTool(name: string, args: Record<string, unknown>): Promise<{
        text: string;
        isError: boolean;
    }>;
    close(): Promise<void>;
}