Overrided GET /mcp to return 405 to avoid opening a long living stream (#33)

Author: kpto

pyproject.toml

@@ -31,6 +31,8 @@ dependencies = [
     "jq>=1.10.0",
     "typer>=0.20.0",
     "pydantic-settings>=2.12.0",
+    "fastapi>=0.136.0",
+    "starlette>=0.50.0",
 ]
 
 [project.scripts]

src/open_targets_platform_mcp/cli.py

@@ -1,8 +1,13 @@
 import asyncio
 from importlib import metadata
-from typing import Annotated
+from typing import Annotated, Any
 
 import typer
+import uvicorn
+from fastapi import FastAPI
+from fastapi.responses import JSONResponse
+from starlette.middleware.base import BaseHTTPMiddleware
+from starlette.requests import Request
 
 from open_targets_platform_mcp.create_server import create_server
 from open_targets_platform_mcp.settings import TransportType, settings
@@ -151,12 +156,26 @@ def root(
 
     try:
         if settings.transport == TransportType.HTTP:
-            mcp.run(
+
+            class MCPMethodOverrideMiddleware(BaseHTTPMiddleware):
+                async def dispatch(self, request: Request, call_next: Any) -> JSONResponse:
+                    if request.url.path in {"/mcp", "/mcp/"} and request.method in {"GET", "HEAD", "OPTIONS"}:
+                        return JSONResponse(
+                            status_code=405,
+                            content={"error": "Method Not Allowed"},
+                            headers={"Allow": "POST"},
+                        )
+                    return await call_next(request)
+
+            mcp_asgi = mcp.http_app(
+                path="/",
                 transport=settings.transport.value,
-                host=settings.http_host,
-                port=settings.http_port,
                 stateless_http=settings.stateless_http,
             )
+            app = FastAPI(lifespan=mcp_asgi.lifespan)
+            app.mount("/mcp", mcp_asgi)
+            app.add_middleware(MCPMethodOverrideMiddleware)
+            uvicorn.run(app, host=settings.http_host, port=settings.http_port)
         else:
             mcp.run(
                 transport=settings.transport.value,