How can I plug it into an existing net/http server?

[zoedsoupe]

Description:

I’m integrating mcp-go’s SSEServer into my project and need to combine it with other HTTP endpoints (e.g., Kubernetes health checks) in a single server. For clarity, I want to mount the SSEServer under a custom prefix (e.g., /mcp) while leaving my health endpoints at the root (like /live and /ready).

The SSEServer’s ServeHTTP method is designed to handle requests exactly at /sse and /message. When I attempt to register it using http.HandleFunc with a prefix I still encounter 404 errors when accessing /mcp/sse or /mcp/message.

Steps to Reproduce:

1. Initialize an instance of the SSEServer via the mcp-go API.
2. Register the handler using a code snippet similar to:

http.HandleFunc("/ready", readinessHandler)

// assuming s is an already existing MCPServer
sse := server.NewSSEServer(s, "")
http.HandleFunc("/mcp/", sse.ServerHTTP)

log.Fatal(http.listAndServe(":80", nil))

3. Access /mcp/sse, /mcp/message or /sse, /message and observe a 404 response.

Expected Behavior:

• A request at least to /sse should be correctly handled.

Environment:

• Go version: 1.23.5 (using an Alpine-based Docker image)
• mcp-go version: v0.11.2

Additional Context:

• I have verified that endpoints like /live and /ready work as expected.
• The issue appears to be specific to the prefix handling for SSEServer’s endpoints.
• I’m open to suggestions on the correct approach for mounting the SSEServer under a custom path or if this might be a limitation/bug.

Any guidance or recommended changes would be greatly appreciated. Thank you!

[zoedsoupe]

I thought mux would accept something like :80/mcp as base URL but I was wrong... im kinda noob with go but it seems as a limitation of the impl itself

[zoedsoupe]

well, with #45 one could do something like:

http.HandleFunc("/ready", readinessHandler)

// assuming s is an already existing MCPServer
sse := server.NewSSEServer(s, server.WithBasePath("/mcp")
http.HandleFunc("/mcp/", sse.ServerHTTP)

log.Fatal(http.listAndServe(":80", nil))

and now we got it!!!

2025/03/07 15:52:51 Server running on :80
[] 2025/03/07 - 15:52:58 | 200 |  1.728694792s |       127.0.0.1 | GET      "/mcp/sse"
[] 2025/03/07 - 15:53:08 | 400 |     205.041µs |       127.0.0.1 | POST     "/mcp/message"
[] 2025/03/07 - 15:53:17 | 200 |      27.292µs |       127.0.0.1 | GET      "/ready"