Semantic Kernel
Microsoft's enterprise SDK for AI apps (.NET, Python, Java)
Verdict
Production-ready for .NET and Azure shops, with native Azure service connectors and managed identity. Microsoft now positions Agent Framework as the successor to Semantic Kernel and AutoGen, combining SK's enterprise features with AutoGen's agent abstractions, and publishes a migration guide. Existing SK apps are fine to keep running; for new agent work in C#, evaluate Agent Framework first.
Other Frameworks & SDKs
- LangChainProduction
Composable LLM application framework — chains, agents, RAG
- LlamaIndexProduction
Data framework for LLM applications — indexing and retrieval
- DSPyStable
Stanford framework for programming (not prompting) LMs
- HaystackStable
Deepset open-source NLP framework for production LLM pipelines
- InstructorProduction
Structured outputs from LLMs using Pydantic schemas
- Vercel AI SDKProduction
TypeScript toolkit for building AI-powered web applications