Microsoft Semantic Kernel is an AI orchestration SDK for building multi-agent systems, process workflows, and LLM-powered applications. It provides a unified abstraction layer over multiple AI providers (OpenAI, Azure, Google, Mistral, Ollama, HuggingFace, etc.) and supports function calling, plugin systems, prompt templates, memory/vector stores, and content safety filters. The framework is implemented in both Python and .NET with consistent architectural patterns. In production, the system acts as a library that developers embed into their applications. The central Kernel class manages service registration, plugin loading, and function execution. Agents (ChatCompletionAgent, AzureAIAgent, etc.) provide conversational interfaces with tool-calling capabilities. The process framework enables event-driven, multi-step workflows with state persistence. The filter system allows cross-cutting concerns like logging, moderation, and quality checks to be injected into function invocation and prompt rendering pipelines. Key entry points include the Kernel class, agent classes, ProcessBuilder for workflows, and various sample scripts. Data flows typically involve user input being processed by an agent or kernel, which invokes AI services via connectors, optionally calls plugins/functions, and returns responses. The framework relies on external AI services, vector databases, and optionally Dapr for distributed process execution. While primarily an application framework, Semantic Kernel includes data/research-oriented components such as vector store integrations, embedding generation services, and quality evaluation filters, making it a hybrid tool suitable for both production AI applications and experimental research.