Originally published on NextFuture Anthropic's Mythos and OpenAI's GPT-5.5-Cyber sit behind allowlists covering fewer than 200 organizations as of May 2026. These five tools — open weights, hosted APIs, and self-hostable stacks — address the same defensive surface area with no application required. For full context on why the frontier cyber models are restricted, see Inside the AI Cyber Arms Race (May 2026) . TL;DR: The 2026 winners ToolBest ForHostingStarts AtAllowlist? Llama Guard 3 (8B)Content filtering at app layerSelf-host / HF Inference APIFree / $0.0004 per 1k tokensNo SentinelSphere 2.1Real-time agent threat detectionCloud SaaS$49/mo StarterNo Google Cloud Security AI WorkbenchCloud log triage and forensicsGCP managed~$0.12 per 1k security eventsNo CyberSecEval 3Pre-deploy LLM capability evaluationSelf-host (GitHub, Apache 2.0)FreeNo Microsoft PyRIT + OWASP LLM Top 10 v2Prompt red-teaming and threat modelingSelf-host (pip install)FreeNo Enter fullscreen mode Exit fullscreen mode How I selected these…