[Python] MCP Server is giving "The selected tool does not have a callable 'function'" when...

This is all running MCP server and I have also validated it via cloude desktop

from typing import Dict
from mcp.server.fastmcp import FastMCP

# Initialize the FastMCP server with a name
mcp = FastMCP("simple_weather")

# Weather data for different topics
WEATHER_DATA = {
"rain": {
"description": "Rain is liquid water in droplets that falls from clouds",
"measurement": "Measured in millimeters or inches",
"effects": "Can cause flooding in heavy amounts",
},
}


# Define the weather info tool using the @mcp.tool decorator
@mcp.tool()
async def get_weather_info(topic: str) -> Dict[str, str]:
"""
A tool to fetch weather-related information based on the topic.

Arguments:
- topic: The weather topic (rain, temperature, wind, etc.)

Returns:
- A dictionary containing the weather description, measurement, and effects
"""
topic = topic.lower() # Normalize topic to lowercase
if topic not in WEATHER_DATA:
return {
"error": f"Unknown weather topic '{topic}'",
"available_topics": list(WEATHER_DATA.keys()),
}
return WEATHER_DATA[topic]


# Run the MCP server when the script is executed
if __name__ == "__main__":
mcp.run()




Now, I want to use it via local client, these things I am doing

1. running dummy server like : uv run dummy_server.py
2. running this autogen client

import asyncio
from autogen_ext.tools.mcp import McpWorkbench, StdioServerParams
from autogen_ext.models.openai import OpenAIChatCompletionClient


async def run_chat_with_topic(topic: str):
server_params = StdioServerParams(
command="python",
args=["dummy_server.py"],
read_timeout_seconds=60,
)
workbench = McpWorkbench(server_params=server_params)

all_tools = await workbench.list_tools()

selected_tool = next(
(
tool
for tool in all_tools
if isinstance(tool, dict) and tool.get("name") == "get_weather_info"
),
None,
)

if not selected_tool:
raise ValueError("Tool 'get_weather_info' not found on the MCP server.")

# Call the selected tool's function
if "function" in selected_tool:
result = await selected_tool["function"](topic=topic)
else:
raise ValueError("The selected tool does not have a callable 'function'.")

model_client = OpenAIChatCompletionClient(model="gpt-3.5-turbo")

from autogen_agentchat.agents import AssistantAgent
from autogen_agentchat.conditions import MaxMessageTermination
from autogen_agentchat.teams import RoundRobinGroupChat

assistant_1 = AssistantAgent(
name="Planner",
model_client=model_client,
system_message="You are an AI weather planner for India.",
tools=[selected_tool],
reflect_on_tool_use=True,
tool_call_summary_format="[Tool]{tool_name} result : {result}",
)

assistant_2 = AssistantAgent(
name="Researcher",
model_client=model_client,
system_message="You are an AI weather researcher for India.",
tools=[selected_tool],
reflect_on_tool_use=True,
tool_call_summary_format="[Tool]{tool_name} result : {result}",
)

agents = [assistant_1, assistant_2]

termination_condition = MaxMessageTermination(max_message_number=len(agents) + 1)

team = RoundRobinGroupChat(
agents=agents,
termination_condition=termination_condition,
)

return await team.run(
task=[{"role": "user", "content": f"Get weather info for '{topic}'"}]
)


if __name__ == "__main__":
topic = "rain"

asyncio.run(run_chat_with_topic(topic))



but I am getting this error

line 36, in run_chat_with_topic
raise ValueError("The selected tool does not have a callable 'function'.")
ValueError: The selected tool does not have a callable 'function'.


it seems MCP server is giving this kind of tool definition

{'name': 'get_weather_info', 'description': '\n A tool to fetch
weather-related information based on the topic.\n\n
Arguments:\n - topic: The weather topic (rain, temperature, wind, etc.)
\n\n Returns:\n - A dictionary containing the weather description,
measurement, and effects\n ',
'parameters': {'type': 'object', 'properties': {'topic':
{'title': 'Topic', 'type': 'string'}},
'required': ['topic'], 'additionalProperties': False}}


seems It don't have any definition of function like : 'function': get_weather_info_function, can you please help me here

these are version I am using here

dependencies = [
"autogen-agentchat>=0.5.5",
"autogen-ext[openai]>=0.5.5",
"httpx>=0.28.1",
"mcp[cli]>=1.7.1",
]

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