Bug: plugin functions not loaded into ChatCompletionAgent when using kernel.CreatePluginFromObject()

[jjgriff93]

Describe the bug
I have some code that creates a number of agents dynamically, each with a stateful plugin created from a new object instance (following the example in the docs):

public static ChatCompletionAgent CreatePlayerAgent(Kernel kernel, int playerId, string initialRole)
{
    // Clone kernel instance to allow for agent specific plug-in definition
    Kernel agentKernel = kernel.Clone();

    // Initialize plug-in from object
    agentKernel.CreatePluginFromObject(new WerewolfPlayerPlugin(playerId, initialRole));

    // Create the agent
    return
      new ChatCompletionAgent()
      {
        Name = playerId.ToString(),
        Kernel = agentKernel,
        Instructions = Prompts.PlayerInstructions,
        Arguments = new KernelArguments(
          new OpenAIPromptExecutionSettings()
          {
            FunctionChoiceBehavior = FunctionChoiceBehavior.Auto()
          }
        )
        {
          { "playerId", playerId },
          ...
        }
      };
}

The plugin itself only has one KernelFunction:

public class WerewolfPlayerPlugin
{
  public int playerId;
  public string initialRole;

  public WerewolfPlayerPlugin(int playerId, string initialRole)
  {
    this.playerId = playerId;
    this.initialRole = initialRole;
  }

  [KernelFunction("vote")]
  [Description("Vote for another player to be eliminated")]
  public async Task Vote(
    [Description("The number of the player you want to vote for")]
    int id
  )
  {
    Console.WriteLine($"Player {playerId} voted for player {id}");
    Werewolf.CurrentVotes[playerId] = id;
  }
}

When initiating a group chat, I can see from the trace output that the function isn't being loaded:

Choice:auto, AutoInvoke:True, AllowConcurrentInvocation:False, AllowParallelCalls:(null) Functions:None (Function calling is disabled)

However, when I replace the CreatePluginFromObject with:

agentKernel.Plugins.AddFromObject(new WerewolfPlayerPlugin(playerId, initialRole));

It loads just fine:

Choice:auto, AutoInvoke:True, AllowConcurrentInvocation:False, AllowParallelCalls:(null) Functions:WerewolfPlayerPlugin-vote

Looking at the code I believe the example in the docs is incorrect as the plugin isn't added to the plugins collection after being created within the CreatePluginFromObject function:

semantic-kernel/dotnet/src/SemanticKernel.Core/KernelExtensions.cs

Line 406 in 2984423

return KernelPluginFactory.CreateFromObject(target, pluginName, kernel.LoggerFactory);

Whereas in Plugins.AddFromObject it is:

semantic-kernel/dotnet/src/SemanticKernel.Core/KernelExtensions.cs

Line 676 in 2984423

plugins.Add(plugin);

Platform

• Language: C#
• Source: Microsoft.SemanticKernel.Agents.Core Version=1.37.0-alpha
• AI model: GPT-4o
• IDE: VS Code
• OS: Mac

[jjgriff93]

Raised an issue on docs: MicrosoftDocs/semantic-kernel-docs#211
And PR to fix: MicrosoftDocs/semantic-kernel-docs#212

If this is indeed the expected functionality (which I believe it is) then this issue can be closed in favour of the docs issue above

[crickman]

Yes, the docs are incorrect.