Forty-eight percent of cybersecurity professionals now identify agentic AI as the number-one attack vector heading into 2026 — ahead of ransomware, deepfakes, and supply chain compromise. Yet only 34% of enterprises have AI-specific security controls in place. That gap is where autonomous agents do their damage. In December 2025, OWASP published the Top 10 for Agentic Applications 2026 (ASI01–ASI10): the first peer-reviewed taxonomy of security risks unique to autonomous AI systems. Three months later, on April 2, 2026, Microsoft released the Agent Governance Toolkit under MIT license — the first open-source project to address all ten OWASP Agentic risks through a deterministic, sub-millisecond policy engine. This guide maps each OWASP risk to the specific toolkit module that addresses it, walks through the architecture, and shows developers how to get a governed agent running in under 10 minutes.…