add workaround for lack of request object in MCP runtime

app.py

@@ -57,7 +57,9 @@ def generate_prompt(request: gr.Request):
         The new system prompt.
     """
     try:
-        session_id = request.session_hash
+        # Currently, gradio doesn't offer session/user tracking for MCP usage.
+        # https://www.gradio.app/guides/building-mcp-server-with-gradio#limitations
+        session_id = request.session_hash or "(unknown ID)"
 
         # Read the system prompt from file
         system_prompt = os.environ.get("SYSTEM_PROMPT")