Client stuck state Waiting for server to respond to `initialize` request...

dhruv-bansal commented 4 weeks ago

I am trying to run simple use case - to expose existing APIs on MCP server as tools and then test it from the MCP client

config file for mcp-access-point

access_point:
  listeners:
    - address: 0.0.0.0:8080

mcps:
  - id: test
    upstream_id: 1
    path: https://petstore.swagger.io/v2/swagger.json

MCP client configuration

{
    "servers": {
        "test": {
            "url": "http://localhost:8080/api/test/sse"
        }
    }
}

MCP client kept waiting for 'initialize request'

[info] Starting server test
[info] Connection state: Starting
[info] Starting server from LocalProcess extension host
[info] Connection state: Running
[info] Waiting for server to respond to `initialize` request...
[info] Waiting for server to respond to `initialize` request...
[info] Waiting for server to respond to `initialize` request...
[info] Waiting for server to respond to `initialize` request...

Logs for mcp-access-point

DEBUG pingora_core::services::listening] new event!
DEBUG pingora_core::protocols::http::v1::server] Client prematurely closed connection with 0 byte sent
DEBUG pingora_core::protocols::l4::stream] Dropping socket Some(BufStream { inner: BufReader { reader: BufWriter { writer: RawStreamWrapper { stream: Tcp(PollEvented { io: Some(TcpStream { addr: 172.17.0.2:8080, peer: 192.168.65.1:54506, fd: 15 }) }), rx_ts: None, enable_rx_ts: false, reusable_cmsg_space: [] }, buffer: 0/1460, written: 0 }, buffer: 0/65536 } })
DEBUG pingora_core::services::listening] new event!
DEBUG pingora_proxy] Successfully get a new request
DEBUG access_point::proxy::route] match request: host=Some("localhost"), uri="/api/test/sse", method="POST"
DEBUG access_point::service::mcp] ctx.route_params: None
WARN  access_point::service::mcp] Route(/api/test/sse) not found
DEBUG access_point::utils::request] match_api_path: /api/test/sse
DEBUG access_point::service::mcp] Request path: Some(/api/test/sse)
DEBUG access_point::utils::request] match_api_path: /api/test/sse
DEBUG access_point::service::mcp] SSE path: "/api/test/sse"
DEBUG access_point::service::mcp] tenant_id: test
DEBUG pingora_core::services::listening] new event!
DEBUG pingora_proxy] Successfully get a new request
DEBUG access_point::proxy::route] match request: host=Some("localhost"), uri="/api/test/sse", method="GET"
DEBUG access_point::service::mcp] ctx.route_params: None
WARN  access_point::service::mcp] Route(/api/test/sse) not found
DEBUG access_point::utils::request] match_api_path: /api/test/sse
DEBUG access_point::service::mcp] Request path: Some(/api/test/sse)
DEBUG access_point::utils::request] match_api_path: /api/test/sse
DEBUG access_point::service::mcp] SSE path: "/api/test/sse"
DEBUG access_point::service::mcp] tenant_id: test

sxhxliang commented 4 weeks ago

What MCP client and version are you using?

dhruv-bansal commented 4 weeks ago

I’m currently using VS Code and a mcp.config file for testing purposes as my MCP client. As far as I know, I’m not relying on any specific MCP-related extensions inside VS Code. Both client and mcp-server config as quoted above.

Let me explain my use case for better context:

I have a set of existing (legacy) microservices that already expose their APIs and OpenAPI specifications, available at the endpoint /v3/api-docs on each microservice.
I don't want to modify these microservices to integrate MCP logic directly.
From my understanding, mcp-access-point can act as a bridge here. If I configure mcp-access-point to point to my microservices’ OpenAPI endpoint(s), it should act as an MCP server that exposes those APIs as tools.
Once exposed, I should be able to use any MCP-compatible client (in my case, VS Code) to connect to this MCP server and view all available tools (i.e., the APIs exposed via the microservices).

This is the core of my use case and what I’m trying to achieve.

However, I’m currently unable to see the tools listed after setting this up — and I'm unsure if the issue lies in my configuration, understanding, or the way I'm testing with VS Code.

sxhxliang commented 4 weeks ago

I tested MCP Inspector and Cursor Desktop, both work fine. Have you tried these two clients? btw, I'll test VS Code and reply later.

sxhxliang commented 3 weeks ago

Thanks for reporting this. I've been able to reproduce the issue you described. This was a bug in VS Code. Refer to the discussion of the following issues microsoft/vscode#248949 microsoft/vscode#246753 modelcontextprotocol/python-sdk#530

dhruv-bansal commented 3 weeks ago

Thanks for the input @sxhxliang End to end flow starts working atleast for the GET APIs. I am facing other problem for which I will be opening other issues.

sxhxliang / mcp-access-point

Client stuck state Waiting for server to respond to `initialize` request... #4