InvalidOperationException("No service for type 'System.Collections.Generic.IEnumerable1[Microsoft.SemanticKernel.KernelPlugin] has been registered.

[HappyNomad]

I'm partially transitioning a project from only Semantic Kernel to using some Micorosoft.Extensions.AI (so that I can use the evals library). In doing so, I'm running into an blocking issue.

When I run this code:

var service = kernel.GetRequiredService<IChatCompletionService>().AsChatClient();
service = ChatClientBuilderChatClientExtensions.AsBuilder(service).UseFunctionInvocation().Build();
var settings = new ChatOptions
{
  Tools = kernel.Plugins.SelectMany<KernelPlugin, AITool>(p => p.AsAIFunctions()).ToList(),
  ToolMode = ChatToolMode.Auto
};
var result = await service.GetResponseAsync(chatHistory, settings);

Although the correct tool call is being "queued up" in the result's Role=Assistant message, the Role=tool message that follows it has a "Contents" property with this exception message:

InvalidOperationException("No service for type 'System.Collections.Generic.IEnumerable1[Microsoft.SemanticKernel.KernelPlugin] has been registered."

What am I doing wrong? Although I have no idea why it's searching for a KernelPlugin collection, I tried registering one using dependency injection but it didn't work.

[Samielakkad]

You are combining Semantic Kernel functions with the Microsoft.Extensions.AI function-invocation pipeline, but the generated AIFunction objects are not being given the kernel they need for invocation.

KernelPlugin.AsAIFunctions has an optional Kernel parameter specifically for this:

https://learn.microsoft.com/en-us/dotnet/api/microsoft.semantickernel.kernelplugin.asaifunctions

Pass the existing kernel while converting the plugins:

IChatClient client = kernel
    .GetRequiredService<IChatCompletionService>()
    .AsChatClient()
    .AsBuilder()
    .UseFunctionInvocation()
    .Build();

var tools = kernel.Plugins
    .SelectMany(plugin => plugin.AsAIFunctions(kernel))
    .Cast<AITool>()
    .ToList();

var settings = new ChatOptions
{
    Tools = tools,
    ToolMode = ChatToolMode.Auto,
};

var result = await client.GetResponseAsync(chatHistory, settings);

The Semantic Kernel implementation clones each KernelFunction with the supplied kernel. Calling AsAIFunctions() with no argument leaves that default kernel unset, which matters when invocation needs the kernel's plugins/services.

Also use only one automatic invocation layer:

• With the Microsoft.Extensions.AI pipeline above, let UseFunctionInvocation() invoke the AIFunction tools.
• Alternatively, stay with Semantic Kernel's IChatCompletionService and FunctionChoiceBehavior.Auto(), passing the kernel to the Semantic Kernel call.

Do not enable both automatic loops for the same request. UseFunctionInvocation() already receives tool calls, invokes the matching function from ChatOptions.Tools, appends the tool result, and calls the inner client again.

Registering IEnumerable<KernelPlugin> in DI is therefore treating the symptom. The plugins already exist in kernel.Plugins; the missing connection is passing that kernel into the converted functions.