Microsoft's Agent Framework has reached general availability as a full production runtime, not just an SDK. The Agent Harness — the core runtime wrapping AI models with function invocation, history persistence, context compaction, planning, tool approval, and built-in OpenTelemetry — is now GA alongside Foundry Hosted Agents. Build 2026 also brought stable connectors for GitHub Copilot SDK and Claude Agent SDK, enabling governed multi-agent orchestration without custom adapters. A key insight from an MBZUAI analysis of Claude Code's source is that ~98.4% of a real-world agent codebase is harness infrastructure, not AI logic — validating the harness-first approach. Orchestration patterns (sequential, parallel, Magentic) share one API, and all coding-agent traffic flows through unified OpenTelemetry traces and Foundry dashboards. The framework is available in .NET and Python.
