How to set parameters in tasks.json for rake task in VSCODE

When execute from cmd, I would input something like: rake task001 url=site1 Now I need to run the rake task inside VSCODE, the tasks.json as below:

{
"version": "2.0.0",
"tasks": [
    {
        "type": "rake",
        "task": "task001",
        "args": [
            {
                "url": "site1"
            }
        ]
    }
]

}

That failed to pass the parameter to rake task, with "Property args is not allowed"

Anyone know how to make this work?