Refactor SSE endpoints to /mcp and fix library type errors

src/monarch_mcp_custom/server.py

@@ -13,7 +13,8 @@ from dotenv import load_dotenv
 from fastmcp import FastMCP
 from starlette.applications import Starlette
 from starlette.responses import JSONResponse
-from starlette.routing import Route, Mount
+from starlette.routing import Route
+from mcp.server.sse import SseServerTransport
 import uvicorn
 
 from monarch_mcp_custom.auth import get_authenticated_client
@@ -144,8 +145,8 @@ async def get_account_holdings(account_id: str) -> str:
     """Get investment holdings for a specific account."""
     try:
         client = await get_authenticated_client()
-        # Ensure account_id is treated correctly (usually string ID in Monarch)
-        holdings = await client.get_account_holdings(account_id)
+        # The library expects an int for account_id
+        holdings = await client.get_account_holdings(int(account_id))
         return serialize_json(holdings)
     except Exception as e:
         logger.error(f"Failed to get holdings: {e}")
@@ -157,7 +158,8 @@ async def refresh_accounts() -> str:
     """Request a refresh of account data from financial institutions."""
     try:
         client = await get_authenticated_client()
-        result = await client.request_accounts_refresh()
+        # Request refresh for all accounts (empty list often means all in this library)
+        result = await client.request_accounts_refresh([])
         return serialize_json(result)
     except Exception as e:
         logger.error(f"Failed to refresh accounts: {e}")
@@ -176,15 +178,29 @@ async def health_check(request):
 
 
 def create_app():
-    """Create the Starlette application with MCP mounted at /mcp."""
-    mcp_app = mcp.http_app()
+    """Create the Starlette application with MCP at /mcp."""
+    # SSE Transport following the "newer http-streamable" convention:
+    # Stream endpoint at /mcp, messages at /mcp/messages
+    sse = SseServerTransport("/mcp/messages")
+
+    async def handle_sse(request):
+        async with sse.connect_sse(request.scope, request.receive, request._send) as (
+            read_stream,
+            write_stream,
+        ):
+            await mcp.run(
+                read_stream,
+                write_stream,
+                mcp.create_initialization_options(),
+            )
 
     routes = [
         Route("/health", health_check, methods=["GET"]),
-        Mount("/mcp", app=mcp_app),
+        Route("/mcp", endpoint=handle_sse, methods=["GET"]),
+        Route("/mcp/messages", endpoint=sse.handle_post_message, methods=["POST"]),
     ]
 
-    return Starlette(routes=routes, lifespan=mcp_app.lifespan)
+    return Starlette(routes=routes, lifespan=mcp.lifespan)
 
 
 app = create_app()