.Net: Removing KernelAgent.cs and moving its functionality into Agent.cs (#11244)

### Description

Removing `KernelAgent` to decrease the number of layers in the Agent
Framework.

- Moved functionality of `KernelAgent` to `Agent`
- Moved tests from `KernelAgentTests` to `AgentTests`
- Removed `KernelAgent` and `KernelAgentTests`
- Renamed `ChatHistoryKernelAgent` to `ChatHistoryAgent`

### Contribution Checklist

<!-- Before submitting this PR, please make sure: -->

- [x] The code builds clean without any errors or warnings
- [x] The PR follows the [SK Contribution
Guidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
and the [pre-submission formatting
script](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [x] All unit tests pass, and I have added new tests where possible
- [x] I didn't break anyone 😄

---------

Co-authored-by: Ben Thomas <[email protected]>

Author: alliscode

dotnet/samples/Concepts/Agents/ChatCompletion_ServiceSelection.cs

@@ -7,7 +7,7 @@ namespace Agents;
 
 /// <summary>
 /// Demonstrate service selection for <see cref="ChatCompletionAgent"/> through setting service-id
-/// on <see cref="KernelAgent.Arguments"/> and also providing override <see cref="KernelArguments"/>
+/// on <see cref="Agent.Arguments"/> and also providing override <see cref="KernelArguments"/>
 /// when calling <see cref="ChatCompletionAgent.InvokeAsync(ChatHistory, KernelArguments?, Kernel?, CancellationToken)"/>
 /// </summary>
 public class ChatCompletion_ServiceSelection(ITestOutputHelper output) : BaseAgentsTest(output)

dotnet/samples/Concepts/Agents/OpenAIAssistant_Templating.cs

@@ -38,7 +38,7 @@ Always state the requested style of the poem.
         // Create the agent
         OpenAIAssistantAgent agent = new(assistant, this.AssistantClient)
         {
-            Arguments =
+            Arguments = new()
             {
                 {"style", "haiku"}
             },
@@ -105,7 +105,7 @@ await this.AssistantClient.CreateAssistantFromTemplateAsync(
         // Create the agent
         OpenAIAssistantAgent agent = new(assistant, this.AssistantClient, plugins: null, templateFactory, templateFormat)
         {
-            Arguments =
+            Arguments = new()
             {
                 {"style", "haiku"}
             },

dotnet/samples/GettingStartedWithAgents/AzureAIAgent/Step01_AzureAIAgent.cs

@@ -26,7 +26,7 @@ public async Task UseTemplateForAzureAgentAsync()
             templateFactory: new KernelPromptTemplateFactory(),
             templateFormat: PromptTemplateConfig.SemanticKernelTemplateFormat)
         {
-            Arguments =
+            Arguments = new()
             {
                 { "topic", "Dog" },
                 { "length", "3" }

dotnet/samples/GettingStartedWithAgents/OpenAIAssistant/Step01_Assistant.cs

@@ -26,7 +26,7 @@ public async Task UseTemplateForAssistantAgentAsync()
             templateFactory: new KernelPromptTemplateFactory(),
             templateFormat: PromptTemplateConfig.SemanticKernelTemplateFormat)
         {
-            Arguments =
+            Arguments = new()
             {
                 { "topic", "Dog" },
                 { "length", "3" }

dotnet/samples/GettingStartedWithAgents/Step01_Agent.cs

@@ -151,7 +151,7 @@ public async Task UseTemplateForChatCompletionAgentAsync()
             new(templateConfig, templateFactory)
             {
                 Kernel = this.CreateKernelWithChatCompletion(),
-                Arguments =
+                Arguments = new()
                     {
                         { "topic", "Dog" },
                         { "length", "3" },

dotnet/samples/GettingStartedWithProcesses/Step04/KernelExtensions.cs

@@ -21,7 +21,7 @@ public static IChatHistoryProvider GetHistory(this Kernel kernel) =>
     /// <summary>
     /// Access an agent as a keyed service.
     /// </summary>
-    public static TAgent GetAgent<TAgent>(this Kernel kernel, string key) where TAgent : KernelAgent =>
+    public static TAgent GetAgent<TAgent>(this Kernel kernel, string key) where TAgent : Agent =>
         kernel.Services.GetRequiredKeyedService<TAgent>(key);
 
     /// <summary>

dotnet/src/Agents/Abstractions/Agent.cs

@@ -6,6 +6,7 @@
 using System.Threading.Tasks;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.SemanticKernel.Arguments.Extensions;
 using Microsoft.SemanticKernel.ChatCompletion;
 
 namespace Microsoft.SemanticKernel.Agents;
@@ -44,6 +45,32 @@ public abstract class Agent
     /// </summary>
     public ILoggerFactory? LoggerFactory { get; init; }
 
+    /// <summary>
+    /// Gets the arguments for the agent instruction parameters (optional).
+    /// </summary>
+    /// <remarks>
+    /// Also includes <see cref="PromptExecutionSettings"/>.
+    /// </remarks>
+    public KernelArguments? Arguments { get; init; }
+
+    /// <summary>
+    /// Gets the instructions for the agent (optional).
+    /// </summary>
+    public string? Instructions { get; init; }
+
+    /// <summary>
+    /// Gets the <see cref="Kernel"/> containing services, plugins, and filters for use throughout the agent lifetime.
+    /// </summary>
+    /// <value>
+    /// The <see cref="Kernel"/> containing services, plugins, and filters for use throughout the agent lifetime. The default value is an empty Kernel, but that can be overridden.
+    /// </value>
+    public Kernel Kernel { get; init; } = new();
+
+    /// <summary>
+    /// Gets or sets a prompt template based on the agent instructions.
+    /// </summary>
+    protected IPromptTemplate? Template { get; set; }
+
     /// <summary>
     /// Invoke the agent with no message assuming that all required instructions are already provided to the agent or on the thread.
     /// </summary>
@@ -222,6 +249,27 @@ public abstract IAsyncEnumerable<AgentResponseItem<StreamingChatMessageContent>>
     /// </summary>
     protected virtual ILoggerFactory ActiveLoggerFactory => this.LoggerFactory ?? NullLoggerFactory.Instance;
 
+    /// <summary>
+    /// Formats the system instructions for the agent.
+    /// </summary>
+    /// <param name="kernel">The <see cref="Kernel"/> containing services, plugins, and other state for use by the agent.</param>
+    /// <param name="arguments">Optional arguments to pass to the agents's invocation, including any <see cref="PromptExecutionSettings"/>.</param>
+    /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.</param>
+    /// <returns>The formatted system instructions for the agent.</returns>
+    protected async Task<string?> RenderInstructionsAsync(Kernel kernel, KernelArguments? arguments, CancellationToken cancellationToken)
+    {
+        if (this.Template is null)
+        {
+            // Use the instructions as-is
+            return this.Instructions;
+        }
+
+        var mergedArguments = this.Arguments.Merge(arguments);
+
+        // Use the provided template as the instructions
+        return await this.Template.RenderAsync(kernel, mergedArguments, cancellationToken).ConfigureAwait(false);
+    }
+
     /// <summary>
     /// Set of keys to establish channel affinity.  Minimum expected key-set:
     /// <example>

dotnet/src/Agents/Abstractions/Agents.Abstractions.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <!-- THIS PROPERTY GROUP MUST COME FIRST -->
@@ -20,6 +20,7 @@
     <Compile Include="$(RepoRoot)/dotnet/src/InternalUtilities/src/Diagnostics/*" Link="%(RecursiveDir)Utilities/%(Filename)%(Extension)" />
     <Compile Include="$(RepoRoot)/dotnet/src/InternalUtilities/src/System/AppContextSwitchHelper.cs" Link="%(RecursiveDir)Utilities/%(Filename)%(Extension)" />
     <Compile Include="$(RepoRoot)/dotnet/src/InternalUtilities/agents/Extensions/AgentExtensions.cs" Link="%(RecursiveDir)Utilities/%(Filename)%(Extension)" />
+    <Compile Include="$(RepoRoot)/dotnet/src/InternalUtilities/arguments/Extensions/KernelArgumentsExtensions.cs" Link="%(RecursiveDir)Utilities/%(Filename)%(Extension)" />
   </ItemGroup>
 
   <ItemGroup>

dotnet/src/Agents/Abstractions/KernelAgent.cs

@@ -10,7 +10,7 @@ namespace Microsoft.SemanticKernel.Agents.AzureAI;
 /// <summary>
 /// Provides an <see cref="AIProjectClient"/> for use by <see cref="AzureAIAgent"/>.
 /// </summary>
-public sealed partial class AzureAIAgent : KernelAgent
+public sealed partial class AzureAIAgent : Agent
 {
     /// <summary>
     /// Produces a <see cref="AIProjectClient"/>.

dotnet/src/Agents/AzureAI/AzureAIAgent.ClientFactory.cs

@@ -16,9 +16,9 @@
 namespace Microsoft.SemanticKernel.Agents.AzureAI;
 
 /// <summary>
-/// Provides a specialized <see cref="KernelAgent"/> based on an Azure AI agent.
+/// Provides a specialized <see cref="Agent"/> based on an Azure AI agent.
 /// </summary>
-public sealed partial class AzureAIAgent : KernelAgent
+public sealed partial class AzureAIAgent : Agent
 {
     /// <summary>
     /// Provides tool definitions used when associating a file attachment to an input message:
@@ -200,7 +200,7 @@ async IAsyncEnumerable<ChatMessageContent> InternalInvokeAsync()
                 options?.ToAzureAIInvocationOptions(),
                 this.Logger,
                 options?.Kernel ?? this.Kernel,
-                this.MergeArguments(options?.KernelArguments),
+                options?.KernelArguments,
                 cancellationToken).ConfigureAwait(false))
             {
                 // The thread and the caller should be notified of all messages regardless of visibility.
@@ -252,8 +252,6 @@ public IAsyncEnumerable<ChatMessageContent> InvokeAsync(
         async IAsyncEnumerable<ChatMessageContent> InternalInvokeAsync()
         {
             kernel ??= this.Kernel;
-            arguments = this.MergeArguments(arguments);
-
             await foreach ((bool isVisible, ChatMessageContent message) in AgentThreadActions.InvokeAsync(this, this.Client, threadId, options, this.Logger, kernel, arguments, cancellationToken).ConfigureAwait(false))
             {
                 if (isVisible)
@@ -311,7 +309,7 @@ public async IAsyncEnumerable<AgentResponseItem<StreamingChatMessageContent>> In
         var invokeResults = this.InvokeStreamingAsync(
             azureAIAgentThread.Id!,
             options?.ToAzureAIInvocationOptions(),
-            this.MergeArguments(options?.KernelArguments),
+            options?.KernelArguments,
             options?.Kernel ?? this.Kernel,
             newMessagesReceiver,
             cancellationToken);
@@ -388,8 +386,6 @@ public IAsyncEnumerable<StreamingChatMessageContent> InvokeStreamingAsync(
         IAsyncEnumerable<StreamingChatMessageContent> InternalInvokeStreamingAsync()
         {
             kernel ??= this.Kernel;
-            arguments = this.MergeArguments(arguments);
-
             return AgentThreadActions.InvokeStreamingAsync(this, this.Client, threadId, messages, options, this.Logger, kernel, arguments, cancellationToken);
         }
     }
@@ -425,7 +421,7 @@ protected override async Task<AgentChannel> CreateChannelAsync(CancellationToken
 
     internal Task<string?> GetInstructionsAsync(Kernel kernel, KernelArguments? arguments, CancellationToken cancellationToken)
     {
-        return this.FormatInstructionsAsync(kernel, arguments, cancellationToken);
+        return this.RenderInstructionsAsync(kernel, arguments, cancellationToken);
     }
 
     /// <inheritdoc/>

dotnet/src/Agents/AzureAI/AzureAIAgent.cs

@@ -16,9 +16,9 @@
 namespace Microsoft.SemanticKernel.Agents.Bedrock;
 
 /// <summary>
-/// Provides a specialized <see cref="KernelAgent"/> for the Bedrock Agent service.
+/// Provides a specialized <see cref="Agent"/> for the Bedrock Agent service.
 /// </summary>
-public sealed class BedrockAgent : KernelAgent
+public sealed class BedrockAgent : Agent
 {
     /// <summary>
     /// The client used to interact with the Bedrock Agent service.
@@ -136,8 +136,7 @@ public override async IAsyncEnumerable<AgentResponseItem<ChatMessageContent>> In
         });
 
         // Invoke the agent
-        var arguments = this.MergeArguments(options?.KernelArguments);
-        var invokeResults = this.InvokeInternalAsync(invokeAgentRequest, arguments, cancellationToken);
+        var invokeResults = this.InvokeInternalAsync(invokeAgentRequest, options?.KernelArguments, cancellationToken);
 
         // Return the results to the caller in AgentResponseItems.
         await foreach (var result in invokeResults.ConfigureAwait(false))
@@ -180,8 +179,6 @@ public async IAsyncEnumerable<AgentResponseItem<ChatMessageContent>> InvokeAsync
         AgentInvokeOptions? options = null,
         [EnumeratorCancellation] CancellationToken cancellationToken = default)
     {
-        var arguments = this.MergeArguments(options?.KernelArguments);
-
         // The provided thread is used to continue the conversation. If the thread is not provided and the session id is provided,
         // a new thread is created with the provided session id. If neither is provided, a new thread is created.
         if (thread is null && invokeAgentRequest.SessionId is not null)
@@ -200,7 +197,7 @@ public async IAsyncEnumerable<AgentResponseItem<ChatMessageContent>> InvokeAsync
         invokeAgentRequest = this.ConfigureAgentRequest(options, () => invokeAgentRequest);
 
         // Invoke the agent
-        var invokeResults = this.InvokeInternalAsync(invokeAgentRequest, arguments, cancellationToken);
+        var invokeResults = this.InvokeInternalAsync(invokeAgentRequest, options?.KernelArguments, cancellationToken);
 
         // Return the results to the caller in AgentResponseItems.
         await foreach (var result in invokeResults.ConfigureAwait(false))
@@ -368,8 +365,7 @@ public override async IAsyncEnumerable<AgentResponseItem<StreamingChatMessageCon
         });
 
         // Invoke the agent
-        var arguments = this.MergeArguments(options?.KernelArguments);
-        var invokeResults = this.InvokeStreamingInternalAsync(invokeAgentRequest, bedrockThread, arguments, cancellationToken);
+        var invokeResults = this.InvokeStreamingInternalAsync(invokeAgentRequest, bedrockThread, options?.KernelArguments, cancellationToken);
 
         // Return the results to the caller in AgentResponseItems.
         await foreach (var result in invokeResults.ConfigureAwait(false))
@@ -413,8 +409,6 @@ public async IAsyncEnumerable<AgentResponseItem<StreamingChatMessageContent>> In
         AgentInvokeOptions? options = null,
         [EnumeratorCancellation] CancellationToken cancellationToken = default)
     {
-        var arguments = this.MergeArguments(options?.KernelArguments);
-
         // The provided thread is used to continue the conversation. If the thread is not provided and the session id is provided,
         // a new thread is created with the provided session id. If neither is provided, a new thread is created.
         if (thread is null && invokeAgentRequest.SessionId is not null)
@@ -432,7 +426,7 @@ public async IAsyncEnumerable<AgentResponseItem<StreamingChatMessageContent>> In
         invokeAgentRequest.SessionId = bedrockThread.Id;
         invokeAgentRequest = this.ConfigureAgentRequest(options, () => invokeAgentRequest);
 
-        var invokeResults = this.InvokeStreamingInternalAsync(invokeAgentRequest, bedrockThread, arguments, cancellationToken);
+        var invokeResults = this.InvokeStreamingInternalAsync(invokeAgentRequest, bedrockThread, options?.KernelArguments, cancellationToken);
 
         // The Bedrock agent service has the same API for both streaming and non-streaming responses.
         // We are invoking the same method as the non-streaming response with the streaming configuration set,

dotnet/src/Agents/Bedrock/BedrockAgent.cs

@@ -44,7 +44,7 @@ public sealed class AgentGroupChat : AgentChat
     /// <summary>
     /// Add an <see cref="Agent"/> to the chat.
     /// </summary>
-    /// <param name="agent">The <see cref="KernelAgent"/> to add.</param>
+    /// <param name="agent">The <see cref="Agent"/> to add.</param>
     public void AddAgent(Agent agent)
     {
         if (this._agentIds.Add(agent.Id))