Securing AI Agents with the Microsoft Agent Governance Toolkit

Stop shipping AI agents with no security model. Microsoft released the Agent Governance Toolkit on April 2, 2026, and it's the first toolkit to address every item in the OWASP Agentic AI Top 10 with deterministic, sub-millisecond runtime policy enforcement. This book is how you put it to work.Most agent security content stops at prompt injection. Real production agents face ten distinct risks: tool misuse, privilege compromise, resource overload, memory poisoning, cascading hallucination, intent breaking, misaligned behavior, repudiation, identity spoofing, and overwhelming the human-in-the-loop. The OWASP Agentic AI Top 10 names them. The Microsoft Agent Governance Toolkit gives you the primitives to enforce them at runtime. This book maps each risk to its correct control layer and builds the enforcement code in production-quality Python, .NET, and Go.What you will build:- A trust-boundary model with immutable principal identity, tool identity, and execution context that threads a correlation ID through every governance hook- Versioned policy rule sets with default-deny, prioritized evaluators, and a local test harness that fails CI on shadowing bugs- Execution-ring routing that sends low-risk tools through an in-process Rust FFI evaluator and high-risk tools through a process-isolated worker- A control coverage matrix and gap analyzer that maps the OWASP Agentic AI Top 10 to the right defense layer and flags false confidence- Cross-framework delegation tokens with Ed25519 signatures, audience binding, expiry, and replay-nonce protection across Python, .NET, and a Go mesh sidecar- Phase-gated shared memory that prevents a compromised fulfillment agent from reading credentials written during intake- Immutable audit records with correlation IDs that survive sandbox boundaries and cross-framework handoffs, plus failure classification for runtime exceptions versus policy denials- Production deployment patterns: per-attachment fail-mode configuration, channel-gated policy promotion, automated rollback, drift detection, and health probes wired to agent-sreWhat makes this book different:- Real OWASP Agentic AI Top 10, not LLM Top 10. Most agent security content recycles the OWASP LLM list. This book maps to the actual Agentic spec published December 2025.- Cross-framework, not Python-only. A single TravelSupportAgent reference application runs across the OpenAI Agents SDK in Python and the Microsoft Agent Framework in .NET, with a Go mesh sidecar enforcing network-layer policy and a Rust hot-path evaluator under the runtime.- Production-honest. Process isolation is called process isolation, not full sandboxing. HMAC and shared secrets are explicitly rejected for cross-organizational delegation. Demos versus production are clearly distinguished.- Real toolkit packages. Every install command, namespace, and API matches the Microsoft Agent Governance Toolkit shipped April 2, 2026: agent-os-kernel, agentmesh-platform, agentmesh-runtime, agent-sre, and agent-governance-toolkit.Covers the public preview release of the Microsoft Agent Governance Toolkit (April 2026), including the policy evaluation engine, zero-trust identity with decentralized identifiers and the Inter-Agent Trust Protocol, execution rings with worker isolation, audit and SLO observability, and the OWASP verification CLI. Maps directly to the OWASP Agentic AI Top 10 (December 2025).Prerequisites: Intermediate Python and .NET. Comfort with at least one agent framework (OpenAI Agents SDK, Microsoft Agent Framework, LangGraph, Google ADK, CrewAI, Haystack, or PydanticAI). Basic Go and Rust reading ability for the sidecar and FFI evaluator chapters. No prior agent security experience required.Governance belongs inside the agent loop. Build it the right way before your agents face production traffic. Read more