Getting error 404 even after using mcp-proxy

[Ordinary0x]

jre/bin/java -jar mcp-proxy/build/libs/mcp-proxy-all.jar --sse-url http://127.0.0.1:9876/sse

2025-12-26 01:56:53.035 [main] INFO Main - Starting Burp MCP proxy with SSE URL: http://127.0.0.1:9876/sse
2025-12-26 01:56:53.440 [main] ERROR SseClient - Failed to connect to SSE server at http://127.0.0.1:9876/sse: Expected status code 200 but was 404
2025-12-26 01:56:53.441 [main] WARN Main - Please check if the server is running and the URL is correct
2025-12-26 01:56:53.441 [main] INFO Main - Will attempt to reconnect automatically when needed
2025-12-26 01:56:53.442 [DefaultDispatcher-worker-1] INFO SseClient - Starting to monitor SSE server availability...
2025-12-26 01:56:53.448 [main] ERROR Main - Failed to start proxy: Server does not support tools (required for ToolsList)
java.lang.IllegalStateException: Server does not support tools (required for ToolsList)
at io.modelcontextprotocol.kotlin.sdk.server.Server.assertRequestHandlerCapability(Server.kt:707)
at io.modelcontextprotocol.kotlin.sdk.shared.Protocol.setRequestHandler(Protocol.kt:445)
at net.portswigger.MainKt.setupRequestHandlers$lambda$7(Main.kt:267)
at net.portswigger.MainKt.withClient(Main.kt:143)
at net.portswigger.MainKt.setupRequestHandlers(Main.kt:147)
at net.portswigger.MainKt.access$setupRequestHandlers(Main.kt:1)
at net.portswigger.MainKt$sseToStdio$1.invokeSuspend(Main.kt:48)
at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:98)
at kotlinx.coroutines.EventLoopImplBase.processNextEvent(EventLoop.common.kt:263)
at kotlinx.coroutines.BlockingCoroutine.joinBlocking(Builders.kt:94)
at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking(Builders.kt:70)
at kotlinx.coroutines.BuildersKt.runBlocking(Unknown Source)
at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking$default(Builders.kt:48)
at kotlinx.coroutines.BuildersKt.runBlocking$default(Unknown Source)
at net.portswigger.MainKt.sseToStdio(Main.kt:27)
at net.portswigger.MainKt.main(Main.kt:252)

i have done in many ways but i don't why this error is coming .
My sse working correctly , but i need Stdio for my project .
I saw many people raised this issue in the https://github.com/PortSwigger/mcp-server , But no proper solution for this.

[secfb]

I'm getting the same error.

[besendorf]

Same error here. Any ideas how to fix this?

[beyefendi]

The fix https://github.com/beyefendi/mcp-proxy/blob/main/ERROR.md