Fix tool_calls parsing error in ToolCallingAgent (#160)

src/smolagents/agents.py

@@ -15,6 +15,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import time
+import json
 from dataclasses import dataclass
 from typing import Any, Callable, Dict, List, Optional, Tuple, Union
 
@@ -806,9 +807,17 @@ class ToolCallingAgent(MultiStepAgent):
                 tools_to_call_from=list(self.tools.values()),
                 stop_sequences=["Observation:"],
             )
+            
+            # Extract tool call from model output
+            if type(model_message.tool_calls) is list and len(model_message.tool_calls) > 0:
                 tool_calls = model_message.tool_calls[0]
                 tool_arguments = tool_calls.function.arguments
                 tool_name, tool_call_id = tool_calls.function.name, tool_calls.id
+            else:
+                start, end = model_message.content.find('{'), model_message.content.rfind('}') + 1
+                tool_calls = json.loads(model_message.content[start:end])
+                tool_arguments = tool_calls["tool_arguments"]
+                tool_name, tool_call_id = tool_calls["tool_name"], f"call_{len(self.logs)}"
 
         except Exception as e:
             raise AgentGenerationError(