Hacker News Reader

Comment by tosh | Hacker News Reader

"error creating connector"

our MCP also works fine with Claude, Claude Code, Amp, lm studio and other but not all MCP clients

MCP spec and client implementations are a bit tricky when you're not using FastMCP (which we are not).

I wonder if it's a difference between SSE and HTTP streaming support? I've been working on a tool for devs to create their own MCP tools and built out support for both protocols because it was easier for me to support both protocols vs explaining why it's not working for one LLM client or another.

Oh, that might be it!

Ours doesn’t support SSE.

mine does support SSE (https://github.com/mickael-kerjean/filestash) but it fails before getting there, with the log looking like this:

    2025/09/11 01:16:13 HTTP 200 GET    0.1ms /.well-known/oauth-authorization-server
    2025/09/11 01:16:13 HTTP 200 GET    2.5ms /
    2025/09/11 01:16:14 HTTP 404 GET    0.2ms /favicon.svg
    2025/09/11 01:16:14 HTTP 404 GET    0.2ms /favicon.png
    2025/09/11 01:16:14 HTTP 200 GET    0.2ms /favicon.ico
    2025/09/11 01:16:14 HTTP 200 GET    0.1ms /.well-known/oauth-authorization-server
    2025/09/11 01:16:15 HTTP 201 POST    0.3ms /mcp/register
    2025/09/11 01:16:27 HTTP 200 GET    1.4ms /

with the frontend showing: "Error creating connector" and the network call showing: { "detail": "1 validation error for RegisterOAuthClientResponse\n Input should be a valid dictionary or instance of RegisterOAuthClientResponse [type=model_type, input_value='{\"client_id\":\"ChatGPT.Dd...client_secret_basic\"}\\n', input_type=str]\n For further information visit https://errors.pydantic.dev/2.11/v/model_type" }

Reply on news.ycombinator.com