Initialize Agent System

Design the core architecture for your multi-agent system using the OpenAI Agents SDK. Define at least two specialized agents: a 'Code Reviewer Agent' focused on identifying issues and a 'Refactor Suggestor Agent' responsible for generating improved code. Both agents should leverage the o4-mini model for their reasoning capabilities. Provide the Python code for initializing these agents, their initial instructions, and any dummy tool definitions required to simulate their functions.