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[Bug] Failed to initialize MCP client: business-knowledge-query #885

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Open
[Bug] Failed to initialize MCP client: business-knowledge-query#885
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bugSomething isn't workinghelp wantedExtra attention is needed
@Wacume

Description

@Wacume
Wacume
opened on Mar 6, 2026

Describe the bug
sse

To Reproduce
Steps to reproduce the behavior:

public class DirectMcpExample {

public static void main(String[] args) {
    try (McpClientWrapper client = createMcpClient()) {
        System.out.println("MCP客户端创建成功");

        // 注册MCP工具
        Toolkit toolkit = new Toolkit();
        toolkit.registerMcpClient(client)
                .doOnSuccess(c -> System.out.println("MCP工具注册成功: " + client.getName()))
                .block();

        // 获取并显示工具列表
        client.listTools()
                .doOnNext(tools -> {
                    System.out.println("可用工具数量: " + tools.size());
                    tools.forEach(tool ->
                            System.out.println("  - " + tool.name() + ": " + tool.description())
                    );
                })
                .block();

        System.out.println("测试完成");
    } catch (Exception e) {
        System.err.println("操作失败: " + e.getMessage());
    }
}

/**
 * 创建MCP客户端
 */
private static McpClientWrapper createMcpClient() {
    String clientName = "business-knowledge-query";
    String url = "http://xxxxx.com/mcp/abc/sse";

    return McpClientBuilder.create(clientName)
            .sseTransport(url)
            .initializationTimeout(Duration.ofSeconds(10))
            .buildSync();
}

}

Expected behavior
A clear and concise description of what you expected to happen.

Error messages
Detailed error messages.
MCP客户端创建成功
16:48:32.298 [main] INFO io.agentscope.core.tool.McpClientManager -- Registering MCP client: business-knowledge-query
16:48:32.299 [main] INFO io.agentscope.core.tool.mcp.McpSyncClientWrapper -- Initializing MCP sync client: business-knowledge-query
16:48:32.467 [HttpClient-1-Worker-0] ERROR io.modelcontextprotocol.client.transport.HttpClientSseClientTransport -- Error sending message: Absolute endpoint URL does not match the base URL.
16:48:32.468 [boundedElastic-1] ERROR io.agentscope.core.tool.mcp.McpSyncClientWrapper -- Failed to initialize MCP client: business-knowledge-query
java.lang.RuntimeException: Client failed to initialize by explicit API call
at io.modelcontextprotocol.client.LifecycleInitializer.lambda$withInitialization$2(LifecycleInitializer.java:288)
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onError(FluxOnErrorResume.java:94)
at reactor.core.publisher.SerializedSubscriber.onError(SerializedSubscriber.java:124)
at reactor.core.publisher.FluxTimeout$TimeoutMainSubscriber.onError(FluxTimeout.java:220)
at reactor.core.publisher.FluxMap$MapSubscriber.onError(FluxMap.java:134)
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onError(FluxOnErrorResume.java:106)
at reactor.core.publisher.Operators.error(Operators.java:198)
at reactor.core.publisher.MonoError.subscribe(MonoError.java:53)
at reactor.core.publisher.Mono.subscribe(Mono.java:4512)
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onError(FluxOnErrorResume.java:103)
at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.onError(FluxPeekFuseable.java:234)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onError(MonoFlatMap.java:180)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onError(MonoFlatMap.java:180)
at reactor.core.publisher.FluxHandle$HandleSubscriber.onError(FluxHandle.java:213)
at reactor.core.publisher.SerializedSubscriber.onError(SerializedSubscriber.java:124)
at reactor.core.publisher.FluxTimeout$TimeoutMainSubscriber.onError(FluxTimeout.java:220)
at reactor.core.publisher.MonoCreate$DefaultMonoSink.error(MonoCreate.java:205)
at io.modelcontextprotocol.spec.McpClientSession.lambda$sendRequest$9(McpClientSession.java:274)
at reactor.core.publisher.LambdaMonoSubscriber.doError(LambdaMonoSubscriber.java:155)
at reactor.core.publisher.LambdaMonoSubscriber.onError(LambdaMonoSubscriber.java:150)
at reactor.core.publisher.FluxContextWrite$ContextWriteSubscriber.onError(FluxContextWrite.java:121)
at reactor.core.publisher.MonoIgnoreElements$IgnoreElementsSubscriber.onError(MonoIgnoreElements.java:84)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.secondError(MonoFlatMap.java:241)
at reactor.core.publisher.MonoFlatMap$FlatMapInner.onError(MonoFlatMap.java:315)
at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.onError(MonoPeekTerminal.java:258)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:136)
at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2571)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.request(MonoFlatMap.java:194)
at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.request(MonoPeekTerminal.java:139)
at reactor.core.publisher.MonoFlatMap$FlatMapInner.onSubscribe(MonoFlatMap.java:291)
at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.onSubscribe(MonoPeekTerminal.java:152)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onSubscribe(MonoFlatMap.java:117)
at reactor.core.publisher.MonoJust.subscribe(MonoJust.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:53)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:76)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:165)
at reactor.core.publisher.Operators$MonoInnerProducerBase.complete(Operators.java:2812)
at reactor.core.publisher.SinkOneMulticast.tryEmitValue(SinkOneMulticast.java:66)
at reactor.core.publisher.SinkOneSerialized.tryEmitValue(SinkOneSerialized.java:38)
at io.modelcontextprotocol.client.transport.HttpClientSseClientTransport.lambda$connect$5(HttpClientSseClientTransport.java:368)
at reactor.core.publisher.FluxFlatMap$FlatMapMain.onNext(FluxFlatMap.java:388)
at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:122)
at reactor.core.publisher.FluxCreate$BufferAsyncSink.drain(FluxCreate.java:880)
at reactor.core.publisher.FluxCreate$BufferAsyncSink.next(FluxCreate.java:805)
at reactor.core.publisher.FluxCreate$SerializedFluxSink.next(FluxCreate.java:163)
at io.modelcontextprotocol.client.transport.ResponseSubscribers$SseLineSubscriber.hookOnNext(ResponseSubscribers.java:150)
at io.modelcontextprotocol.client.transport.ResponseSubscribers$SseLineSubscriber.hookOnNext(ResponseSubscribers.java:72)
at reactor.core.publisher.BaseSubscriber.onNext(BaseSubscriber.java:160)
at org.reactivestreams.FlowAdapters$FlowToReactiveSubscriber.onNext(FlowAdapters.java:211)
at java.net.http/jdk.internal.net.http.LineSubscriberAdapter$LineSubscription.loop(LineSubscriberAdapter.java:447)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$LockingRestartableTask.run(SequentialScheduler.java:205)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$CompleteRestartableTask.run(SequentialScheduler.java:149)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$SchedulableTask.run(SequentialScheduler.java:230)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler.runOrSchedule(SequentialScheduler.java:303)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler.runOrSchedule(SequentialScheduler.java:256)
at java.net.http/jdk.internal.net.http.LineSubscriberAdapter$LineSubscription.submit(LineSubscriberAdapter.java:188)
at java.net.http/jdk.internal.net.http.LineSubscriberAdapter.onNext(LineSubscriberAdapter.java:95)
at java.net.http/jdk.internal.net.http.LineSubscriberAdapter.onNext(LineSubscriberAdapter.java:53)
at java.net.http/jdk.internal.net.http.Http1Response$Http1BodySubscriber.onNext(Http1Response.java:382)
at java.net.http/jdk.internal.net.http.Http1Response$Http1BodySubscriber.onNext(Http1Response.java:297)
at java.net.http/jdk.internal.net.http.ResponseContent$ChunkedBodyParser.accept(ResponseContent.java:229)
at java.net.http/jdk.internal.net.http.ResponseContent$ChunkedBodyParser.accept(ResponseContent.java:129)
at java.net.http/jdk.internal.net.http.Http1Response$BodyReader.handle(Http1Response.java:790)
at java.net.http/jdk.internal.net.http.Http1Response$BodyReader.handle(Http1Response.java:720)
at java.net.http/jdk.internal.net.http.Http1Response$Receiver.accept(Http1Response.java:612)
at java.net.http/jdk.internal.net.http.Http1Response$BodyReader.tryAsyncReceive(Http1Response.java:750)
at java.net.http/jdk.internal.net.http.Http1AsyncReceiver.flush(Http1AsyncReceiver.java:233)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$LockingRestartableTask.run(SequentialScheduler.java:205)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$CompleteRestartableTask.run(SequentialScheduler.java:149)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$TryEndDeferredCompleter.complete(SequentialScheduler.java:347)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$CompleteRestartableTask.run(SequentialScheduler.java:151)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$SchedulableTask.run(SequentialScheduler.java:230)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
at java.base/java.lang.Thread.run(Thread.java:833)
Suppressed: java.lang.Exception: #block terminated with an error
at reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:103)
at reactor.core.publisher.Mono.block(Mono.java:1728)
at io.modelcontextprotocol.client.McpSyncClient.initialize(McpSyncClient.java:189)
at io.agentscope.core.tool.mcp.McpSyncClientWrapper.lambda$initialize$1(McpSyncClientWrapper.java:78)
at reactor.core.publisher.MonoCallable.call(MonoCallable.java:72)
at reactor.core.publisher.FluxSubscribeOnCallable$CallableSubscribeOnSubscription.run(FluxSubscribeOnCallable.java:228)
at reactor.core.scheduler.SchedulerTask.call(SchedulerTask.java:68)
at reactor.core.scheduler.SchedulerTask.call(SchedulerTask.java:28)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304)
... 3 common frames omitted
Caused by: java.lang.IllegalArgumentException: Absolute endpoint URL does not match the base URL.
at io.modelcontextprotocol.util.Utils.resolveUri(Utils.java:77)
at io.modelcontextprotocol.client.transport.HttpClientSseClientTransport.sendHttpPost(HttpClientSseClientTransport.java:467)
at io.modelcontextprotocol.client.transport.HttpClientSseClientTransport.lambda$sendMessage$12(HttpClientSseClientTransport.java:435)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:132)
... 49 common frames omitted
16:48:32.470 [boundedElastic-1] ERROR io.agentscope.core.tool.McpClientManager -- Failed to register MCP client: business-knowledge-query
java.lang.RuntimeException: Client failed to initialize by explicit API call
at io.modelcontextprotocol.client.LifecycleInitializer.lambda$withInitialization$2(LifecycleInitializer.java:288)
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onError(FluxOnErrorResume.java:94)
at reactor.core.publisher.SerializedSubscriber.onError(SerializedSubscriber.java:124)
at reactor.core.publisher.FluxTimeout$TimeoutMainSubscriber.onError(FluxTimeout.java:220)
at reactor.core.publisher.FluxMap$MapSubscriber.onError(FluxMap.java:134)
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onError(FluxOnErrorResume.java:106)
at reactor.core.publisher.Operators.error(Operators.java:198)
at reactor.core.publisher.MonoError.subscribe(MonoError.java:53)
at reactor.core.publisher.Mono.subscribe(Mono.java:4512)
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onError(FluxOnErrorResume.java:103)
at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.onError(FluxPeekFuseable.java:234)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onError(MonoFlatMap.java:180)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onError(MonoFlatMap.java:180)
at reactor.core.publisher.FluxHandle$HandleSubscriber.onError(FluxHandle.java:213)
at reactor.core.publisher.SerializedSubscriber.onError(SerializedSubscriber.java:124)
at reactor.core.publisher.FluxTimeout$TimeoutMainSubscriber.onError(FluxTimeout.java:220)
at reactor.core.publisher.MonoCreate$DefaultMonoSink.error(MonoCreate.java:205)
at io.modelcontextprotocol.spec.McpClientSession.lambda$sendRequest$9(McpClientSession.java:274)
at reactor.core.publisher.LambdaMonoSubscriber.doError(LambdaMonoSubscriber.java:155)
at reactor.core.publisher.LambdaMonoSubscriber.onError(LambdaMonoSubscriber.java:150)
at reactor.core.publisher.FluxContextWrite$ContextWriteSubscriber.onError(FluxContextWrite.java:121)
at reactor.core.publisher.MonoIgnoreElements$IgnoreElementsSubscriber.onError(MonoIgnoreElements.java:84)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.secondError(MonoFlatMap.java:241)
at reactor.core.publisher.MonoFlatMap$FlatMapInner.onError(MonoFlatMap.java:315)
at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.onError(MonoPeekTerminal.java:258)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:136)
at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2571)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.request(MonoFlatMap.java:194)
at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.request(MonoPeekTerminal.java:139)
at reactor.core.publisher.MonoFlatMap$FlatMapInner.onSubscribe(MonoFlatMap.java:291)
at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.onSubscribe(MonoPeekTerminal.java:152)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onSubscribe(MonoFlatMap.java:117)
at reactor.core.publisher.MonoJust.subscribe(MonoJust.java:55)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:53)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:76)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:165)
at reactor.core.publisher.Operators$MonoInnerProducerBase.complete(Operators.java:2812)
at reactor.core.publisher.SinkOneMulticast.tryEmitValue(SinkOneMulticast.java:66)
at reactor.core.publisher.SinkOneSerialized.tryEmitValue(SinkOneSerialized.java:38)
at io.modelcontextprotocol.client.transport.HttpClientSseClientTransport.lambda$connect$5(HttpClientSseClientTransport.java:368)
at reactor.core.publisher.FluxFlatMap$FlatMapMain.onNext(FluxFlatMap.java:388)
at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:122)
at reactor.core.publisher.FluxCreate$BufferAsyncSink.drain(FluxCreate.java:880)
at reactor.core.publisher.FluxCreate$BufferAsyncSink.next(FluxCreate.java:805)
at reactor.core.publisher.FluxCreate$SerializedFluxSink.next(FluxCreate.java:163)
at io.modelcontextprotocol.client.transport.ResponseSubscribers$SseLineSubscriber.hookOnNext(ResponseSubscribers.java:150)
at io.modelcontextprotocol.client.transport.ResponseSubscribers$SseLineSubscriber.hookOnNext(ResponseSubscribers.java:72)
at reactor.core.publisher.BaseSubscriber.onNext(BaseSubscriber.java:160)
at org.reactivestreams.FlowAdapters$FlowToReactiveSubscriber.onNext(FlowAdapters.java:211)
at java.net.http/jdk.internal.net.http.LineSubscriberAdapter$LineSubscription.loop(LineSubscriberAdapter.java:447)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$LockingRestartableTask.run(SequentialScheduler.java:205)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$CompleteRestartableTask.run(SequentialScheduler.java:149)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$SchedulableTask.run(SequentialScheduler.java:230)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler.runOrSchedule(SequentialScheduler.java:303)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler.runOrSchedule(SequentialScheduler.java:256)
at java.net.http/jdk.internal.net.http.LineSubscriberAdapter$LineSubscription.submit(LineSubscriberAdapter.java:188)
at java.net.http/jdk.internal.net.http.LineSubscriberAdapter.onNext(LineSubscriberAdapter.java:95)
at java.net.http/jdk.internal.net.http.LineSubscriberAdapter.onNext(LineSubscriberAdapter.java:53)
at java.net.http/jdk.internal.net.http.Http1Response$Http1BodySubscriber.onNext(Http1Response.java:382)
at java.net.http/jdk.internal.net.http.Http1Response$Http1BodySubscriber.onNext(Http1Response.java:297)
at java.net.http/jdk.internal.net.http.ResponseContent$ChunkedBodyParser.accept(ResponseContent.java:229)
at java.net.http/jdk.internal.net.http.ResponseContent$ChunkedBodyParser.accept(ResponseContent.java:129)
at java.net.http/jdk.internal.net.http.Http1Response$BodyReader.handle(Http1Response.java:790)
at java.net.http/jdk.internal.net.http.Http1Response$BodyReader.handle(Http1Response.java:720)
at java.net.http/jdk.internal.net.http.Http1Response$Receiver.accept(Http1Response.java:612)
at java.net.http/jdk.internal.net.http.Http1Response$BodyReader.tryAsyncReceive(Http1Response.java:750)
at java.net.http/jdk.internal.net.http.Http1AsyncReceiver.flush(Http1AsyncReceiver.java:233)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$LockingRestartableTask.run(SequentialScheduler.java:205)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$CompleteRestartableTask.run(SequentialScheduler.java:149)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$TryEndDeferredCompleter.complete(SequentialScheduler.java:347)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$CompleteRestartableTask.run(SequentialScheduler.java:151)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$SchedulableTask.run(SequentialScheduler.java:230)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
at java.base/java.lang.Thread.run(Thread.java:833)
Suppressed: java.lang.Exception: #block terminated with an error
at reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:103)
at reactor.core.publisher.Mono.block(Mono.java:1728)
at io.modelcontextprotocol.client.McpSyncClient.initialize(McpSyncClient.java:189)
at io.agentscope.core.tool.mcp.McpSyncClientWrapper.lambda$initialize$1(McpSyncClientWrapper.java:78)
at reactor.core.publisher.MonoCallable.call(MonoCallable.java:72)
at reactor.core.publisher.FluxSubscribeOnCallable$CallableSubscribeOnSubscription.run(FluxSubscribeOnCallable.java:228)
at reactor.core.scheduler.SchedulerTask.call(SchedulerTask.java:68)
at reactor.core.scheduler.SchedulerTask.call(SchedulerTask.java:28)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304)
... 3 common frames omitted
Caused by: java.lang.IllegalArgumentException: Absolute endpoint URL does not match the base URL.
at io.modelcontextprotocol.util.Utils.resolveUri(Utils.java:77)
at io.modelcontextprotocol.client.transport.HttpClientSseClientTransport.sendHttpPost(HttpClientSseClientTransport.java:467)
at io.modelcontextprotocol.client.transport.HttpClientSseClientTransport.lambda$sendMessage$12(HttpClientSseClientTransport.java:435)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:132)
... 49 common frames omitted
16:48:32.470 [main] INFO io.agentscope.core.tool.mcp.McpSyncClientWrapper -- Closing MCP sync client: business-knowledge-query
操作失败: Client failed to initialize by explicit API call

Environment (please complete the following information):

AgentScope-Java Version: [e.g. 1.0.9,

  • Java Version: [e.g. 17]
  • OS: [e.g. macos]

Additional context
curl -v http://xxxxx.com/mcp/abc/sse 时

GET /mcp/abc/sse HTTP/1.1
Host: xxxxx.com
User-Agent: curl/8.7.1
Accept: /

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