Lesson 3: Simple Semantic Kernel chat agent with plugins¶

In this lesson we will a semantic kernel plugins to be able to retrieve stock pricing.

Ensure all pre-requisites are met and installed (including updating the StockService apiKey value in the appSettings.json file using the key from polygon.io).
Switch to Lesson 3 directory:
```
cd ../Lesson3
```
Start by copying appsettings.json from Lesson 1:
```
cp ../Lesson1/appsettings.json .
```
Run program and ask what the current date is:
```
dotnet run
```

At the prompt enter

What is the current date?
 ```

Assistant will give a similar response:

```txt
Assistant > I can't access today's date, but imagine it’s an eternal "Fri-yay," ready for financial fun! How can I help you on this hypothetical day?

Notice it does not provide a specific answer. We can use a Semantic Kernel Plugin to be able to fix that.

In the Plugins directory from Core.Utilities directory review the file named TimeInformationPlugin.cs which has the following content:

using System.ComponentModel;
using Microsoft.SemanticKernel;

namespace Plugins;

public class TimeInformationPlugin
{
    [KernelFunction] 
    [Description("Retrieves the current time in UTC.")]
    public string GetCurrentUtcTime() => DateTime.UtcNow.ToString("R");
}

Next locate TODO: Step 1 in Program.cs and add the following import line:
```
using Core.Utilities.Plugins;
```
Next locate TODO: Step 2 in Program.cs and provide the following line to register the TimeInformationPlugin:
```
kernel.Plugins.AddFromObject(new TimeInformationPlugin());
```
Next locate TODO: Step 3 and add the following line to be able to auto invoke kernel functions:
```
    ToolCallBehavior = ToolCallBehavior.AutoInvokeKernelFunctions
```

Next locate TODO: Step 4 and add the following parameters:

    await foreach (var chatUpdate in chatCompletionService.GetStreamingChatMessageContentsAsync(chatHistory, promptExecutionSettings, kernel))

Re-run the program and ask what the current date is. The current date should be displayed this time:

dotnet run
What is the current date?

Assistant response:

Assistant > Today's date is October 4, 2024. Time flies like an arrow; fruit flies like a banana!

Congratulations you are now using your first Semantic Kernel plugin! Next, we are going to leverage another plugin that will provide a StockService. This plugin is included within the Core.Utilities project. Review the file named StockDataPlugin.cs from Core.Utilities\Plugins which includes 2 functions, one to retrieve the stock price for the current date and another one for a specific date:

using Core.Utilities.Services;
using Core.Utilities.Models;
using Core.Utilities.Extensions;

using Microsoft.SemanticKernel;
using System.ComponentModel;

public class StockDataPlugin(StocksService stockService)
{
    private readonly StocksService _stockService = stockService;

    [KernelFunction, Description("Gets stock price")]
    public async Task<string> GetStockPrice(string symbol)
    {
        string tabularData = (await _stockService.GetStockDailyOpenClose(symbol)).FormatStockData();
        return tabularData;
    }

    [KernelFunction, Description("Gets stock price for a given date")]
    public async Task<string> GetStockPriceForDate(string symbol, DateTime date)
    {
        string tabularData = (await _stockService.GetStockDailyOpenClose(symbol, date)).FormatStockData();
        return tabularData;
    }

}

Next, locate TODO: Step 5 in Program.cs and add import required for StockService:
```
using Core.Utilities.Services;
```

Next locate TODO: Step 6 and provide the following line to register the new StockDataPlugin:

HttpClient httpClient = new();
StockDataPlugin stockDataPlugin = new(new StocksService(httpClient));
kernel.Plugins.AddFromObject(stockDataPlugin);

Next run program and ask stock pricing information:

dotnet run
What is MSFT price?

Assistant response:

Assistant > Hold onto your calculators! The price of MSFT is currently $417.63. 
Looks like it's trying to outshine the stars!