MCPX execution failed: Expecting value: line 1 column 1

Hi,

I integrate mcp_run with crewai following https://docs.mcp.run/integrating/tutorials/mcpx-crewai-python.

Then I installed https://www.mcp.run/G4Vi/weather-service. And set task.yaml as follows:
get_latest_weather_task:
description: >
Get the current weather information using the city name given by {city}
expected_output: >
Detailed current weather information including temperature, humidity, and conditions for {city}
agent: weather_expert

The error log shows:
MCPX tool execution failed: Expecting value: line 1 column 1 (char 0).

I tried several weather-service tools, but the error still the same.