Mythos and GPT-Cyber are locked. Open-source alternatives (CodeLlama Guard, Llama Guard 3, Cisco AI defense) are not. We compared both stacks on 4 defensive tasks—the honest results.
We compared what Anthropic Mythos and OpenAI GPT-5.5-Cyber actually do on offensive testing tasks. Capabilities, refusal patterns, evals, and where each model breaks down.
Anthropic's Mythos and OpenAI's GPT-5.5-Cyber both ship locked behind allowlists. Here's what's inside each model, who actually gets access, and what the rest of us can build today.
Langfuse vs Helicone for LLM observability in 2026: SDK span trees vs one-line proxy plus AI Gateway, pricing, real Claude agent test, and decision tree.
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