Semantic Kernel vs Agent Framework

📋 Executive Summary

Key Finding: Microsoft Agent Framework is the unified successor to both Semantic Kernel and AutoGen, announced October 2025.

Semantic Kernel

Enterprise-ready SDK with plugins, connectors, telemetry. .NET 1.x GA, Python 1.39+

Maintenance Mode

Agent Framework

Unified SDK combining SK + AutoGen. Graph workflows, MCP/A2A support.

Active Development

📅 Evolution Timeline

timeline title Microsoft AI Agent Frameworks Evolution 2023-03 : Semantic Kernel Preview 2024-02 : SK .NET 1.0 GA 2024-11 : SK + AutoGen Convergence Announced 2025-01 : AutoGen 0.4 Released 2025-03 : SK Agent Framework 1.0 GA 2025-10 : Microsoft Agent Framework Preview 2025-11 : Agent Framework Public Preview

⚖️ Comparison Matrix

Aspect	Semantic Kernel	Agent Framework
Status	GA (supported)	Public Preview
Languages	.NET, Python, Java	.NET, Python
Agent Model	Kernel + Plugins	Agent + Tools
Orchestration	Process Framework	Graph Workflows
Multi-Agent	Agent Framework (experimental)	Built-in patterns
Protocols	OpenAPI, Plugins	MCP, A2A, OpenAPI
State Mgmt	Memory abstractions	Thread + Checkpointing
Telemetry	Built-in	OpenTelemetry native
Investment	Maintenance	Primary focus

🏗️ Architecture Comparison

Semantic Kernel Architecture

flowchart LR A["User Request"] --> B[Kernel] B --> C[Plugins] B --> D[Memory] B --> E[Connectors] C --> F[Functions] E --> G["Azure OpenAI"] E --> H[OpenAI]

Agent Framework Architecture

flowchart LR A["User Request"] --> B[Agent] B --> C["Tools/MCP"] B --> D["Thread State"] B --> E[Middleware] B --> F[Workflows] F --> G[Sequential] F --> H[Concurrent] F --> I[Handoff] F --> J[Magentic]

🔄 Migration Path

flowchart TD SK["Semantic Kernel Project"] --> Q{"New Project?"} Q -->|Yes| AF["Use Agent Framework"] Q -->|No| M{"Complex Multi-Agent?"} M -->|Yes| AF M -->|No| STAY["Stay on SK"] STAY --> PLAN["Plan Migration"] PLAN --> AF

Migration Steps:

Replace Kernel → Agent
Replace Plugin → Tool
Move from Microsoft.SemanticKernel.* → Microsoft.Agents.AI.*
Use RunAsync instead of kernel invocation

💻 Code Examples

Semantic Kernel (.NET)

var kernel = Kernel.CreateBuilder()
    .AddAzureOpenAIChatCompletion(deployment, endpoint, apiKey)
    .Build();
kernel.Plugins.AddFromType<MyPlugin>();
var result = await kernel.InvokePromptAsync("Hello");

Agent Framework (.NET)

var agent = new OpenAIClient(apiKey)
    .GetOpenAIResponseClient("gpt-4o-mini")
    .CreateAIAgent(name: "Bot", instructions: "You help users.");
Console.WriteLine(await agent.RunAsync("Hello"));

🗺️ Roadmap & Recommendations

✅ Use Agent Framework If:

• Starting new project
• Need multi-agent orchestration
• Require MCP/A2A protocols
• Want graph-based workflows
• Need checkpointing/durability

⚠️ Stay on Semantic Kernel If:

• Existing production app
• Simple single-agent use case
• Need Java support
• Require GA stability now
• Heavy plugin investment

📚 Authoritative Sources

[1] Microsoft Agent Framework Overview - 2025-10-09
[2] Introducing Agent Framework Blog - 2025-10-01
[3] Agent Framework GitHub - 5.4k stars
[4] SK Roadmap H1 2025 - 2025-02-03
[5] Semantic Kernel GitHub - .NET v1.48+, Python v1.39+

Research date: 2025-11-30 | Confidence: High (official docs)