Expert guidance for building AI agents and multi-agent workflows using Microsoft Agent Framework for .NET. Use when (1) creating AI agents with OpenAI or Azure OpenAI, (2) implementing function tools and structured outputs, (3) building multi-turn conversations, (4) designing graph-based workflows with streaming/checkpointing, (5) implementing middleware pipelines, (6) orchestrating multi-agent systems with fan-out/fan-in patterns, (7) adding human-in-the-loop interactions, (8) integrating OpenTelemetry observability, or (9) exposing agents as MCP tools.