Add blocking and logging related tests for MCP streamable HTTP route.

gateway/common/mcp_utils.py

@@ -89,6 +89,7 @@ async def hook_tool_call(
     guardrails_result = await session.get_guardrails_check_result(
         message, action=GuardrailAction.BLOCK
     )
+    print("[hook_tool_call] Guardrails result:", guardrails_result, flush=True)
     # If the request is blocked, return a message indicating the block reason.
     # If there are new errors, run append_and_push_trace in background.
     # If there are no new errors, just return the original request.

gateway/routes/mcp_streamable.py

@@ -81,8 +81,9 @@ async def mcp_post_streamable_gateway(request: Request) -> StreamingResponse:
 
     # Intercept the request and check for guardrails.
     if not is_initialization_request:
-        if result := await _intercept_request(session_id, request_body) and result:  # noqa: F821 pylint: disable=used-before-assignment
-            return result
+        request_interception_result = await _intercept_request(session_id, request_body)
+        if request_interception_result:
+            return request_interception_result
 
     async with httpx.AsyncClient(timeout=CLIENT_TIMEOUT) as client:
         try: