Function call_tool 

pub async fn call_tool(
    proxy_url: &str,
    tool_name: &str,
    args: &HashMap<String, Value>,
    raw_args: Option<&[String]>,
) -> Result<Value, ProxyError>

Execute a tool call via the proxy server.

POST {proxy_url}/call with JSON body: { tool_name, args } Scopes are carried inside the JWT — not in the request body.

args carries key-value pairs for HTTP/MCP tools. raw_args, if provided, is sent as an array in the args field for CLI tools.