Building Intelligent Agentic Systems with .NET 8 and Semantic Kernel

Introduction

Intelligent agentic systems are transitioning from experimental toys to critical enterprise drivers. In this post, we will explore how to build a multi-agent orchestration pipeline using .NET 8 and Microsoft Semantic Kernel. Rather than relying on simple prompt templates, we will design coordinate-controller agents that communicate via state buckets and execute custom semantic functions.

Why .NET 8 for Agentic Orchestration?

.NET 8 brings high-performance native compilation, native AOT compile speeds, and robust dependency injection structures. When coordinating multiple asynchronous agent loops that invoke external API endpoints, C# Task Parallel Library (TPL) provides precise control over rate-limits, execution retries, and cancellation tokens.

Core Architecture of a Multi-Agent System

An agent pipeline consists of three central pillars:

• Orchestrator: Receives the user prompt and routes execution goals to sub-agents.
• Sub-Agents: Specialized workers equipped with local plugins (e.g., SQL search tools, email senders, calendar inspectors).
• State Manager: A shared scratchpad (stored in Redis or Cosmos DB) tracking historical reasoning steps.

Implementation Snippet

Here is how we register a Semantic Kernel assistant with custom tools:

var builder = Kernel.CreateBuilder();
builder.AddOpenAIChatCompletion("gpt-4o", "your-api-key");
var kernel = builder.Build();

// Import system plugin
kernel.ImportPluginFromType<DatabaseToolPlugin>();

In the next post, we will discuss how to implement memory vector search embeddings in Cosmos DB for semantic retrieval.