listTools() and the other no-arg list*() methods follow the cursor chain without any bound

import com.sun.net.httpserver.HttpServer;
import io.modelcontextprotocol.client.McpClient;
import io.modelcontextprotocol.client.McpSyncClient;
import io.modelcontextprotocol.client.transport.HttpClientStreamableHttpTransport;
import io.modelcontextprotocol.spec.McpSchema;

import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.nio.charset.StandardCharsets;
import java.time.Duration;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Repro {

    static final Pattern ID = Pattern.compile("\"id\"\\s*:\\s*(\"(?:[^\"\\\\]|\\\\.)*\"|\\d+)");
    static final Pattern METHOD = Pattern.compile("\"method\"\\s*:\\s*\"([^\"]+)\"");
    static final Pattern VERSION = Pattern.compile("\"protocolVersion\"\\s*:\\s*\"([^\"]+)\"");
    static final AtomicInteger pages = new AtomicInteger();

    public static void main(String[] args) throws Exception {
        HttpServer server = HttpServer.create(
                new InetSocketAddress(InetAddress.getLoopbackAddress(), 0), 0);
        server.createContext("/mcp", exchange -> {
            String body;
            try (InputStream in = exchange.getRequestBody()) {
                body = new String(in.readAllBytes(), StandardCharsets.UTF_8);
            }
            if (!"POST".equalsIgnoreCase(exchange.getRequestMethod())) {
                exchange.sendResponseHeaders(405, -1);
                exchange.close();
                return;
            }
            String method = group(METHOD, body, "");
            if (method.startsWith("notifications/")) {
                exchange.sendResponseHeaders(202, -1);
                exchange.close();
                return;
            }
            String id = group(ID, body, "\"1\"");
            String response = switch (method) {
                case "initialize" -> "{\"jsonrpc\":\"2.0\",\"id\":" + id + ",\"result\":{"
                        + "\"protocolVersion\":\"" + group(VERSION, body, "2025-06-18") + "\","
                        + "\"capabilities\":{\"tools\":{}},"
                        + "\"serverInfo\":{\"name\":\"endless\",\"version\":\"0.0.1\"}}}";
                case "tools/list" -> {
                    int page = pages.incrementAndGet();
                    if (page % 1000 == 0) {
                        System.out.println("served " + page + " pages of tools/list...");
                    }
                    // The only hostile line: nextCursor is non-null, non-empty, and never ends.
                    yield "{\"jsonrpc\":\"2.0\",\"id\":" + id + ",\"result\":{\"tools\":[{"
                            + "\"name\":\"tool_" + page + "\",\"description\":\"Page " + page + "\","
                            + "\"inputSchema\":{\"type\":\"object\",\"properties\":{}}}],"
                            + "\"nextCursor\":\"page-" + page + "\"}}";
                }
                default -> "{\"jsonrpc\":\"2.0\",\"id\":" + id
                        + ",\"error\":{\"code\":-32601,\"message\":\"Method not found\"}}";
            };
            byte[] bytes = response.getBytes(StandardCharsets.UTF_8);
            exchange.getResponseHeaders().set("Content-Type", "application/json");
            exchange.sendResponseHeaders(200, bytes.length);
            try (OutputStream out = exchange.getResponseBody()) {
                out.write(bytes);
            }
        });
        server.start();

        String url = "http://" + server.getAddress().getHostString() + ":" + server.getAddress().getPort();
        McpSyncClient client = McpClient
                .sync(HttpClientStreamableHttpTransport.builder(url).endpoint("/mcp").build())
                .requestTimeout(Duration.ofSeconds(5)) // bounds each request, not the call below
                .build();
        client.initialize();

        System.out.println("calling listTools() — expected: returns; actual: never returns");
        McpSchema.ListToolsResult result = client.listTools();
        System.out.println("unreachable: " + result.tools().size());
    }

    static String group(Pattern pattern, String text, String fallback) {
        Matcher matcher = pattern.matcher(text);
        return matcher.find() ? matcher.group(1) : fallback;
    }
}