Use warning for non standard mcp protocols (#331)

Signed-off-by: Madhav Kandukuri <[email protected]>

Author: madhav165

mcpgateway/cache/session_registry.py

@@ -657,11 +657,7 @@ async def handle_initialize_logic(self, body: dict) -> InitializeResult:
             )
 
         if protocol_version != settings.protocol_version:
-            raise HTTPException(
-                status_code=status.HTTP_400_BAD_REQUEST,
-                detail=f"Unsupported protocol version: {protocol_version}",
-                headers={"MCP-Error-Code": "-32003"},
-            )
+            logger.warning(f"Using non default protocol version: {protocol_version}")
 
         return InitializeResult(
             protocolVersion=settings.protocol_version,

tests/unit/mcpgateway/cache/test_session_registry.py

@@ -28,6 +28,7 @@
 # Standard
 import asyncio
 import json
+import logging
 import re
 from typing import Any, Dict, List
 from unittest.mock import AsyncMock, Mock, patch
@@ -480,11 +481,13 @@ async def test_handle_initialize_missing_version_error(registry: SessionRegistry
 
 
 @pytest.mark.asyncio
-async def test_handle_initialize_unsupported_version_error(registry: SessionRegistry):
+async def test_handle_initialize_unsupported_version_warning(registry: SessionRegistry, caplog):
+    caplog.set_level(logging.WARNING, logger="mcpgateway.cache.session_registry")
     body = {"protocol_version": "999"}
-    with pytest.raises(HTTPException) as exc:
-        await registry.handle_initialize_logic(body)
-    assert exc.value.headers["MCP-Error-Code"] == "-32003"
+
+    await registry.handle_initialize_logic(body)
+
+    assert "Using non default protocol version: 999" in caplog.text
 
 
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