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Expected Behavior

yaml config

    mcp:
      client:
        toolcallback:
          enabled: true
        stdio:
          servers-configuration: classpath:mcp.json
        sse:
          connections:
            server1: http://localhost:5678/mcp/get_user_info/sse

spring error

Factory method 'mcpSyncClients' threw exception with message: Failed to wait for the message endpoint

n8n mcp server config

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Current Behavior

Currently, it can only be accessed via stdio.

Context

Comment From: tzolov

@An0nymous0 how to reproduce this issue. Is there a easy way to create n8n instance with mcp server

Comment From: An0nymous0

@An0nymous0 how to reproduce this issue. Is there a easy way to create n8n instance with mcp server

  1. Visit this address (a simple example):

https://n8n.io/workflows/3514-build-an-mcp-server-with-google-calendar-and-custom-functions/

  1. Click on "Use Free."

  2. Get started for free with n8n Cloud.

  3. "My Functions Server" is an MCP server.

Image

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This will create an n8n MCP instance.

Comment From: denniskawurek

Hi @tzolov , I saw this issue and was wondering whether this is related to the URI resolution problem as described here: https://github.com/modelcontextprotocol/java-sdk/issues/261 At least the error message indicates that the closeLatch in HttpClientSseTransport wasn't called, because of a failed connection attempt to the SSE endpoint.

Comment From: denniskawurek

@An0nymous0 I re-checked this and asked myself if the format of your config is maybe wrong?

The documentation shows that it should be something like this:

        sse:
          connections:
            server1:
              url: http://localhost:5678
              sse-endpoint: /mcp/get_user_info/sse

Could you try this, please? Without warranty as there are few problems with URI resolutions in the underlying library.