fix: update rag cookbook and tool getting

Author: Wendong-Fan

camel/agents/chat_agent.py

@@ -188,7 +188,7 @@ def __init__(
         # the tools set from `ChatAgent` will be used.
         # This design simplifies the interface while retaining tool-running
         # capabilities for `BaseModelBackend`.
-        if all_tools and not self.model_backend.model_config_dict['tools']:
+        if all_tools and not self.model_backend.model_config_dict.get("tools"):
             tool_schema_list = [
                 tool.get_openai_tool_schema() for tool in all_tools
             ]