[Python] Agno Agentic Framework - pydantic code ValidationError

I was trying out the new agentic framework agno and wanted to test it out by writing a simple calculator.

#main.py
def add(x: int, y: int) -> int:
"""
Use this function to add two numbers.
Args:
a (int): The first number.
b (int): The second number.
Returns:
int: The sum of the two numbers.
"""
print("Adding two numbers...")
return x + y

def subtract(x: int, y: int) -> int:
"""
Use this function to subtract two numbers.
Args:
a (int): The first number.
b (int): The second number.
Returns:
int: The difference of the two numbers.
"""
print("Subtracting two numbers...")
return x - y

def multiply(x: int, y: int) -> int:
"""
Use this function to multiply two numbers.
Args:
a (int): The first number.
b (int): The second number.
Returns:
int: The product of the two numbers.
"""
print("Multiplying two numbers...")
return x * y

def generate_random_number() -> int:
"""
Use this function to generate a random number.
Returns:
int: A random number.
"""
print("Generating a random number...")
return 42

def divide(x: int, y: int) -> float:
"""
Use this function to divide two numbers.
Args:
a (int): The first number.
b (int): The second number.
Returns:
float: The quotient of the two numbers.
"""
print("Dividing two numbers...")
return x / y

calculator_agent = Agent(
model=OpenRouter(id="google/gemini-2.0-flash-lite-preview-02-05:free"),
name="Data Agent",
description=dedent("""
You are a helpful calulator agent. You can perform basic arithmetic operations like addition, subtraction, multiplication, and division with the help of the tools provided.
"""),
instructions=[
"""Analyse the user query and use the tools to perform the required operation.""",
],
tools=[add, subtract, multiply, divide, generate_random_number],
show_tool_calls=True,
debug_mode=True,
add_history_to_messages=True,
markdown=True,
)

response = calculator_agent.run("Add 2 to 5. Take the result and multiply it by 2. Take that output and divide it by a random number")
print(response.content)


The error I am getting is

pydantic_core._pydantic_core.ValidationError: 2 validation errors for Message
content.list[any]
Input should be a valid list [type=list_type, input_value=7, input_type=int]
For further information visit https://errors.pydantic.dev/2.11/v/list_type
content.str
Input should be a valid string [type=string_type, input_value=7, input_type=int]
For further information visit https://errors.pydantic.dev/2.11/v/string_type


But I am not stating anywhere that the result of the first addition needs to be a list neither for it to be a String.

Can someone please tell me what I am doing wrong ? Should all custom tools only return types of string ?

There was only one example at : https://docs.agno.com/agents/tools at it does seem to have str as the return type

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