Understanding the kernel

To start creating a kernel, import the necessary packages at the top of your file:

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.SemanticKernel;
using Microsoft.SemanticKernel.Plugins.Core;

Next, you can add services and plugins. Below is an example of how you can add an Azure OpenAI chat completion, a logger, and a time plugin.

// Create a kernel with a logger and Azure OpenAI chat completion service
var builder = Kernel.CreateBuilder();
builder.AddAzureOpenAIChatCompletion(modelId, endpoint, apiKey);
builder.Services.AddLogging(c => c.AddDebug().SetMinimumLevel(LogLevel.Trace));
builder.Plugins.AddFromType<TimePlugin>();
Kernel kernel = builder.Build();

Import the necessary packages:

from semantic_kernel import Kernel
from semantic_kernel.connectors.ai.open_ai import AzureChatCompletion
from semantic_kernel.core_plugins.time_plugin import TimePlugin

Next, you can create a kernel.

# Initialize the kernel
kernel = Kernel()

Finally, you can add the necessary services and plugins. Below is an example of how you can add an Azure OpenAI chat completion, a logger, and a time plugin.

# Add the Azure OpenAI chat completion service
kernel.add_service(AzureChatCompletion(model_id, endpoint, api_key))

# Add a plugin
kernel.add_plugin(
    TimePlugin(),
    plugin_name="TimePlugin",
)

Creating a MCP Server from your Kernel

We now support creating a MCP server from the function you have registered in your Semantic Kernel instance.

In order to do this, you create your kernel as you normally would, and then you can create a MCP server from it.

from semantic_kernel import Kernel
from semantic_kernel.connectors.ai.open_ai import OpenAIChatCompletion
from semantic_kernel.functions import kernel_function
from semantic_kernel.prompt_template import InputVariable, PromptTemplateConfig

kernel = Kernel()

@kernel_function()
def echo_function(message: str, extra: str = "") -> str:
    """Echo a message as a function"""
    return f"Function echo: {message} {extra}"

kernel.add_service(OpenAIChatCompletion(service_id="default"))
kernel.add_function("echo", echo_function, "echo_function")
kernel.add_function(
    plugin_name="prompt",
    function_name="prompt",
    prompt_template_config=PromptTemplateConfig(
        name="prompt",
        description="This is a prompt",
        template="Please repeat this: {{$message}} and this: {{$extra}}",
        input_variables=[
            InputVariable(
                name="message",
                description="This is the message.",
                is_required=True,
                json_schema='{ "type": "string", "description": "This is the message."}',
            ),
            InputVariable(
                name="extra",
                description="This is extra.",
                default="default",
                is_required=False,
                json_schema='{ "type": "string", "description": "This is the message."}',
            ),
        ],
    ),
)
server = kernel.as_mcp_server(server_name="sk")

The server object created above comes from the mcp package, you can extend it even further for instance by adding resources, or other features to it. And then you can bring it online, for instance to be used with Stdio:

import anyio
from mcp.server.stdio import stdio_server

async def handle_stdin(stdin: Any | None = None, stdout: Any | None = None) -> None:
    async with stdio_server() as (read_stream, write_stream):
        await server.run(read_stream, write_stream, server.create_initialization_options())

anyio.run(handle_stdin)

Or with SSE:

import uvicorn
from mcp.server.sse import SseServerTransport
from starlette.applications import Starlette
from starlette.routing import Mount, Route

sse = SseServerTransport("/messages/")

async def handle_sse(request):
    async with sse.connect_sse(request.scope, request.receive, request._send) as (read_stream, write_stream):
        await server.run(read_stream, write_stream, server.create_initialization_options())

starlette_app = Starlette(
    debug=True,
    routes=[
        Route("/sse", endpoint=handle_sse),
        Mount("/messages/", app=sse.handle_post_message),
    ],
)

uvicorn.run(starlette_app, host="0.0.0.0", port=8000)

Exposing prompt templates as MCP Prompt

You can also leverage the different Semantic Kernel prompt templates by exposing them as MCP Prompts, like this:

from semantic_kernel.prompt_template import InputVariable, KernelPromptTemplate, PromptTemplateConfig

prompt = KernelPromptTemplate(
    prompt_template_config=PromptTemplateConfig(
        name="release_notes_prompt",
        description="This creates the prompts for a full set of release notes based on the PR messages given.",
        template=template,
        input_variables=[
            InputVariable(
                name="messages",
                description="These are the PR messages, they are a single string with new lines.",
                is_required=True,
                json_schema='{"type": "string"}',
            )
        ],
    )
)

server = kernel.as_mcp_server(server_name="sk_release_notes", prompts=[prompt])

Build a kernel

Kernels can be built using a Kernel.builder(). On this you can add required AI services and plugins.

Kernel kernel = Kernel.builder()
    .withAIService(ChatCompletionService.class, chatCompletionService)
    .withPlugin(lightPlugin)
    .build();

Using Dependency Injection

In C#, you can use Dependency Injection to create a kernel. This is done by creating a ServiceCollection and adding services and plugins to it. Below is an example of how you can create a kernel using Dependency Injection.

using Microsoft.SemanticKernel;

var builder = Host.CreateApplicationBuilder(args);

// Add the OpenAI chat completion service as a singleton
builder.Services.AddOpenAIChatCompletion(
    modelId: "gpt-4",
    apiKey: "YOUR_API_KEY",
    orgId: "YOUR_ORG_ID", // Optional; for OpenAI deployment
    serviceId: "YOUR_SERVICE_ID" // Optional; for targeting specific services within Semantic Kernel
);

// Create singletons of your plugins
builder.Services.AddSingleton(() => new LightsPlugin());
builder.Services.AddSingleton(() => new SpeakerPlugin());

// Create the plugin collection (using the KernelPluginFactory to create plugins from objects)
builder.Services.AddSingleton<KernelPluginCollection>((serviceProvider) => 
    [
        KernelPluginFactory.CreateFromObject(serviceProvider.GetRequiredService<LightsPlugin>()),
        KernelPluginFactory.CreateFromObject(serviceProvider.GetRequiredService<SpeakerPlugin>())
    ]
);

// Finally, create the Kernel service with the service provider and plugin collection
builder.Services.AddTransient((serviceProvider)=> {
    KernelPluginCollection pluginCollection = serviceProvider.GetRequiredService<KernelPluginCollection>();

    return new Kernel(serviceProvider, pluginCollection);
});