Short-Term Conversation Memory › Memory with Tool Use

def calculate(expression: str) -> dict:
    """Simple calculator tool."""
    try:
        result = eval(expression)
        return {"success": True, "result": result}
    except Exception as e:
        return {"success": False, "error": str(e)}

calculator_tool = {
    "name": "calculate",
    "description": "Perform mathematical calculations",
    "input_schema": {
        "type": "object",
        "properties": {
            "expression": {
                "type": "string",
                "description": "Math expression to evaluate"
            }
        },
        "required": ["expression"]
    }
}

class ConversationalAgentWithTools:
    """Agent with memory and tool use."""
    
    def __init__(self):
        self.client = Anthropic(api_key=os.getenv("ANTHROPIC_API_KEY"))
        self.conversation_history = []
        self.tools = {"calculate": calculate}
    
    def chat(self, user_message: str) -> str:
        """Chat with tool use support."""
        # Add user message
        self.conversation_history.append({
            "role": "user",
            "content": user_message
        })
        
        # Get response
        response = self.client.messages.create(
            model="claude-sonnet-4-5",
            max_tokens=1024,
            tools=[calculator_tool],
            messages=self.conversation_history
        )
        
        # Handle tool use if needed
        if response.stop_reason == "tool_use":
            # Extract tool call
            tool_use_block = next(
                block for block in response.content 
                if block.type == "tool_use"
            )
            
            # Call the tool
            tool_result = self.tools[tool_use_block.name](
                **tool_use_block.input
            )
            
            # Add tool use to history
            self.conversation_history.append({
                "role": "assistant",
                "content": response.content
            })
            
            # Add tool result to history
            self.conversation_history.append({
                "role": "user",
                "content": [{
                    "type": "tool_result",
                    "tool_use_id": tool_use_block.id,
                    "content": str(tool_result)
                }]
            })
            
            # Get final response
            final_response = self.client.messages.create(
                model="claude-sonnet-4-5",
                max_tokens=1024,
                tools=[calculator_tool],
                messages=self.conversation_history
            )
            
            assistant_message = final_response.content[0].text
        else:
            assistant_message = response.content[0].text
        
        # Add final response to history
        self.conversation_history.append({
            "role": "assistant",
            "content": assistant_message
        })
        
        return assistant_message

agent = ConversationalAgentWithTools()

print(agent.chat("What's 1234 times 5678?"))
## Agent uses calculator tool
## "1,234 times 5,678 equals 7,006,652."

print(agent.chat("What if I double that?"))
## Agent remembers the previous result
## Agent calculates 7006652 * 2
## "Doubling that gives you 14,013,304."

print(agent.chat("And what's 10% of the original number?"))
## Agent remembers 7,006,652 was the original
## Agent calculates 7006652 * 0.1
## "10% of the original number (7,006,652) is 700,665.2."