Autonomous agents are moving into production faster than governance frameworks can keep up. Agents call external APIs, write files, delegate sub-tasks to other agents, and run for hours — all without a human watching every step. That creates real exposure: prompt injection, privilege escalation, unintended data exfiltration, and no audit trail when things go wrong. Microsoft released the Agent Governance Toolkit on April 2, 2026 as a MIT-licensed open-source project that sits between your agent framework and the actions agents take. It is the first toolkit to cover all 10 OWASP Agentic AI Top 10 risks with deterministic, sub-millisecond policy enforcement. This guide walks through what it does, how to install it, and how to wire it into frameworks you already use. Effloow Lab verified the package structure, PyPI availability, and integration API surface from the official GitHub repository and Microsoft documentation. See the lab-run note for details and limitations.…