ClawMoat vs LlamaFirewall vs NeMo Guardrails: Which Open-Source AI Agent Security Tool Should You Use?

Three open-source tools. Three different approaches to AI agent security. Three very different threat models. If you're building with LangChain, CrewAI, AutoGen, or any framework that gives your AI agent real capabilities — shell access, file I/O, web browsing — you've probably started thinking about security. The question isn't if your agent will encounter adversarial input, but when . Meta released LlamaFirewall in May 2025. NVIDIA has been iterating on NeMo Guardrails since 2023. And ClawMoat emerged to address a gap neither of them covers: protecting the host machine itself. Let's break them down honestly. Quick Comparison LlamaFirewall NeMo Guardrails ClawMoat Maintainer Meta NVIDIA Independent (open-source) Language Python Python Node.js Dependencies Heavy (ML models) Moderate (LLM calls) Zero Primary focus Prompt injection, jailbreak, alignment Conversational guardrails, topic control Host-level protection, credential monitoring Threat model Adversarial prompts → model Unsafe mo