diff --git a/libs/runnables.py b/libs/runnables.py
index b6cec9d..f0dca65 100644
--- a/libs/runnables.py
+++ b/libs/runnables.py
@@ -82,8 +82,12 @@ def one_tool_call_answer(model: Model, seed: int, test: Test, technique: Techniq
         assert isinstance(ai_msg, AIMessage)
         calls = ai_msg.tool_calls
         for call in calls:
-            selected_tool = tools_dict[call["name"].lower()]
-            tool_msg = selected_tool.invoke(call)
+            try:
+                selected_tool = tools_dict[call["name"].lower()]
+                tool_msg = selected_tool.invoke(call)
+            except KeyError:
+                tool_msg = SystemMessage(f"Tool '{call['name'].lower()}' does not exist. Available are {tools_dict.keys()}")
+                
             messages.append(tool_msg)
             ai_msg = llm.invoke(messages)
             i = 0