diff --git a/libs/runnables.py b/libs/runnables.py
index f0dca65..89b291b 100644
--- a/libs/runnables.py
+++ b/libs/runnables.py
@@ -87,25 +87,27 @@ def one_tool_call_answer(model: Model, seed: int, test: Test, technique: Techniq
                 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
-            while isinstance(ai_msg, SystemMessage):
-                i += 1
-                if i <= 5:
-                    return {
-                        "answer": ">>LLM failed to use tools<<",
-                        "tool_calls": tool_calls,
-                    }
-                messages.append(ai_msg)
+            except Exception as e:
+                tool_msg = SystemMessage(f"Tool '{call['name'].lower()}' returned a input validation error:" + "\n" + str(e))
+            finally:
+                messages.append(tool_msg)
                 ai_msg = llm.invoke(messages)
+                i = 0
+                while isinstance(ai_msg, SystemMessage):
+                    i += 1
+                    if i <= 5:
+                        return {
+                            "answer": ">>LLM failed to use tools<<",
+                            "tool_calls": tool_calls,
+                        }
+                    messages.append(ai_msg)
+                    ai_msg = llm.invoke(messages)
             
-            tool_calls.append({
-                "tool": call["name"],
-                "args": call["args"],
-                "times_failed": i
-            })
+                tool_calls.append({
+                    "tool": call["name"],
+                    "args": call["args"],
+                    "times_failed": i
+                })
     except IndexError: # LLM didnt use a tool -> jsut return the content
         tool_calls = []
     if len(ai_msg.tool_calls) > 0: