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SK vs Agent Framework

Key Points

Aspect Semantic Kernel Microsoft Agent Framework
Position Established (.NET-only origin) New (2026 GA)
Built on Direct OpenAI SDK Microsoft.Extensions.AI
Orchestration Plugins + Planners Multi-agent patterns
Templates Strong (Liquid, Handlebars) Plain strings
OTel Some First-class GenAI
Vendor portability Limited Native via IChatClient
Status (2026) Maintained; some deprecated Default for new

For new projects: Agent Framework. For existing SK: keep + hybrid.

SK strengths

  • Mature prompt template engine.
  • Plugin ecosystem.
  • Process Framework (preview).
  • ChatHistory class.

Agent Framework strengths

  • Built on Microsoft.Extensions.AI — vendor-portable.
  • Native multi-agent orchestration patterns.
  • MCP integration first-class.
  • Better OTel coverage.
  • Aligned with Microsoft.Extensions.AI ecosystem.

When SK shines

  • Heavy prompt templating.
  • Existing Process Framework usage.
  • Existing extensive plugin code.

When Agent Framework shines

  • Multi-agent.
  • Vendor flexibility.
  • Modern observability.
  • Green field.

Code comparison

SK

var kernel = Kernel.CreateBuilder()
    .AddOpenAIChatCompletion("gpt-4o-mini", apiKey)
    .Build();
kernel.Plugins.AddFromType<WeatherPlugin>();

var settings = new OpenAIPromptExecutionSettings { FunctionChoiceBehavior = FunctionChoiceBehavior.Auto() };
var resp = await kernel.GetRequiredService<IChatCompletionService>().GetChatMessageContentAsync(history, settings, kernel);

Agent Framework

IChatClient chat = new OpenAIClient(apiKey).AsChatClient("gpt-4o-mini")
    .AsBuilder().UseFunctionInvocation().Build();
var agent = new ChatClientAgent(chat) { Tools = [AIFunctionFactory.Create(GetWeather)] };
var resp = await agent.InvokeAsync(input);

Less ceremony; more vendor-portable.

Migration path

Incremental:

  1. Add Microsoft.Extensions.AI.
  2. New features: Agent Framework.
  3. Existing SK: keep until rewrite.
  4. Hybrid: SK templates + AF execution.

See Migration from SK and AutoGen.

What's deprecated

  • SK Planners (Sequential, Stepwise, Handlebars).
  • Some Plugin patterns.
  • ChatHistory in some scenarios.

See Deprecated Planners.

What's evolving

  • SK Process Framework.
  • SK templating (continues).
  • Possible convergence with Microsoft.Extensions.AI.

Senior decision

For new code: Agent Framework + Microsoft.Extensions.AI.

For existing: maintain; hybrid where natural; full migration when feature demands.

Don't migrate just to migrate.

Cross-references