```python
from autogen import ConversableAgent, LLMConfig
from dotenv import load_dotenv
import os
load_dotenv()

# Put your key in the OPENAI_API_KEY environment variable
llm_config = llm_config = LLMConfig(config_list={"api_type": "openai", "model": "gpt-5-nano","api_key":os.getenv("OPENAI_API_KEY")})

planner_system_message = """You are a classroom lesson agent.
Given a topic, write a lesson plan for a fourth grade class.
Use the following format:
<title>Lesson plan title</title>
<learning_objectives>Key learning objectives</learning_objectives>
<script>How to introduce the topic to the kids</script>
"""

my_agent = ConversableAgent(
    name="lesson_agent",
    system_message=planner_system_message,
    llm_config=llm_config,
)

# 1. Create our "human" agent
the_human = ConversableAgent(
    name="human",
    human_input_mode="ALWAYS",
)

# 2. Initiate our chat between the agents
the_human.initiate_chat(
    recipient=my_agent,
    message="Today, let's introduce our kids to the solar system."
    )
```
