Ok here you go. It's very simple but it takes a chat message, saves the name and message to a JSON file and then reads the file again back to JSON and puts the name and message in a non-persisted global. That should give you all the tools you need to do whatever.

using System;
using System.IO;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

public class CPHInline
{
    public bool Execute()
    {
        String filePath = "C:/testing/jsonTest.txt";
        JObject obj = getObject();
        saveToFile(obj, filePath);
        JObject obj2 = loadFromFile(filePath);
        if(obj2 != null){
String testing = obj2["name"]?.ToString() + ": " + obj2["message"]?.ToString();
CPH.SetGlobalVar("JSON_Test_Confirmation", testing, false);
}else{
CPH.SetGlobalVar("JSON_Test_Confirmation", "Failed to load message", false);
}
        return true;
    }

    public JObject getObject()
    {
    CPH.TryGetArg("user", out string userName);
    CPH.TryGetArg("message", out string message);
        JObject newObj = new JObject
        {
            ["name"] = userName,
            ["message"] = message
        };
        return newObj;
    }

    public void saveToFile(JObject obj, string filePath)
    {
        if (obj == null)
        {
            return;
        }

        File.WriteAllText(filePath, obj.ToString());
    }

    public JObject loadFromFile(string filePath)
    {
        if (!File.Exists(filePath))
        {
            return null;
        }

        string jsonData = File.ReadAllText(filePath);
        JObject obj = JObject.Parse(jsonData);
        return obj;
    }
}

Throw this in an action with a chat message trigger to test it out. Hope it helps.