Hey. It seems that the MCP Provider faces issues w...

# koog-agentic-framework

[Priyanshu Jain]

Hey.
It seems that the MCP Provider faces issues with hosted MCPs on SSE.
Trying to figure out that whether the issue is with Koog, Ktor or the MCP Server.
Details in the thread (🧵)

[Priyanshu Jain]

By referencing the example/mcp/PlaywrightMcpClient.kt, I tried setting up a similar toolsRegistry but instead of launching the Process locally, I tried to connect with a hosted MCP Server.
Here's my ViewModel code:

class MainViewModel : ViewModel() {

    private val _uiState = MutableStateFlow(ChatScreenUiState())
    val uiState = _uiState.asStateFlow()


    private val systemMessage = """
            You are Beacon, an AI companion.
        """

    private val promptExecutor = simpleOllamaAIExecutor(baseUrl = "<http://10.0.2.2:11434>")
    private var history = prompt("history", LLMParams()) { system(systemMessage) }
    
    private fun runQuery() {
        viewModelScope.launch {
            val toolsRegistry = McpToolRegistryProvider.fromTransport(
                transport = McpToolRegistryProvider.defaultSseTransport("<https://mcp.kite.trade>")
            )
            val response = promptExecutor.execute(
                prompt = history,
                model = OllamaModels.Meta.LLAMA_3_2,
                tools = toolsRegistry.tools.map { it.descriptor }
            )
            val agentMessage = ChatMessage(
                id = UUID.randomUUID().toString(),
                text = response[0].content,
                senderType = SenderType.BOT
            )
            history = prompt(history) {
                system(response[0].content)
            }
            _uiState.update {
                it.copy(isLoading = false, messages = it.messages + agentMessage)
            }
        }
    }

    fun onAction(action: ChatScreenAction) {
        when (action) {
            is ChatScreenAction.OnMessageInput -> {
                _uiState.update { it.copy(currentMessage = action.inputMessage) }
            }

            is ChatScreenAction.SendMessage -> {
                history = prompt(history) {
                    user(action.message)
                }
                val chatMessage = ChatMessage(
                    id = UUID.randomUUID().toString(),
                    text = action.message,
                    senderType = SenderType.USER
                )
                _uiState.update {
                    it.copy(isLoading = true, messages = it.messages + chatMessage)
                }
                runQuery()
            }
        }
    }
}

The app crashed when sending the first message with this log:

FATAL EXCEPTION: main (Ask Gemini)
Process: <http://com.example.app|com.example.app>, PID: 15682
java.lang.IllegalStateException: Error connecting to transport: Server's protocol version is not supported: 2025-03-26
	at io.modelcontextprotocol.kotlin.sdk.client.Client.connect$suspendImpl(Client.kt:105)
	at io.modelcontextprotocol.kotlin.sdk.client.Client$connect$1.invokeSuspend(Unknown Source:15)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:100)
	at android.os.Handler.handleCallback(Handler.java:959)
	at android.os.Handler.dispatchMessage(Handler.java:100)
	at android.os.Looper.loopOnce(Looper.java:232)
	at android.os.Looper.loop(Looper.java:317)
	at android.app.ActivityThread.main(ActivityThread.java:8705)

                                                                                                    	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:580)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:886)
	Suppressed: kotlinx.coroutines.internal.DiagnosticCoroutineContextException: [StandaloneCoroutine{Cancelling}@dc9d687, Dispatchers.Main.immediate]

To get more details, I created a custom SSE transport instance with logging enabled and this is what I got:

HTTP Client: REQUEST: <https://mcp.kite.trade/sse>
METHOD: HttpMethod(value=GET)
COMMON HEADERS
-> Accept: */*
-> Accept-Charset: UTF-8
CONTENT HEADERS
-> Content-Length: 0
-> Accept: text/event-stream
-> Cache-Control: no-store
BODY Content-Type: null
BODY START
BODY END

HTTP Client: RESPONSE: 200 OK
METHOD: HttpMethod(value=GET)
FROM: <https://mcp.kite.trade/sse>
COMMON HEADERS
-> CF-RAY: <>
-> Cache-Control: no-cache
-> Connection: keep-alive
-> Content-Type: text/event-stream
-> Date: Sat, 31 May 2025 07:07:51 GMT
-> Server: cloudflare
-> Set-Cookie: <set-cookie-data>
-> Strict-Transport-Security: max-age=15552000; includeSubDomains
-> Transfer-Encoding: chunked
-> access-control-allow-origin: *
-> alt-svc: h3=":443"; ma=86400
-> cf-cache-status: DYNAMIC
BODY Content-Type: text/event-stream
BODY START
BODY END

HTTP Client: REQUEST: <https://mcp.kite.trade/message?sessionId=><session-id>
METHOD: HttpMethod(value=POST)
COMMON HEADERS
-> Accept: */*
-> Accept-Charset: UTF-8
CONTENT HEADERS
-> Content-Length: 227
-> Content-Type: application/json
BODY Content-Type: application/json
BODY START
{"id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{"experimental":{},"sampling":{}},"clientInfo":{"name":"mcp-client-cli","version":"1.0.0"},"_meta":{},"method":"initialize"},"jsonrpc":"2.0"}
BODY END
app_time_stats: avg=1.63ms min=0.79ms max=4.16ms count=61
HTTP Client: RESPONSE: 202 Accepted
METHOD: HttpMethod(value=POST)
FROM: <https://mcp.kite.trade/message?sessionId=><session-id>
COMMON HEADERS
-> CF-RAY: <>
-> Connection: keep-alive
-> Content-Length: 0
-> Date: Sat, 31 May 2025 07:07:51 GMT
-> Server: cloudflare
-> Set-Cookie:<set-cookie-data> 
-> Strict-Transport-Security: max-age=15552000; includeSubDomains
-> alt-svc: h3=":443"; ma=86400
-> cf-cache-status: DYNAMIC
BODY Content-Type: null
BODY START

BODY END

And then, it fails with the exception detailed above.

[Vadim Briliantov]

cc: @Maria Tigina can it be connected with the recent bug that we are fixing at the moment?

[Maria Tigina]

Thank you for reporting this! It seems like it's not related to the current known problems. I'll create an issue for this specific issue and try to reproduce and figure out on what side is the issue

[Priyanshu Jain]

This works after updating to 0.2.0