Type: AI model
Claude Mythos Preview is the early, limited-access form of Anthropic’s Mythos-class model, tested by a small set of organizations before the broader fifth-generation rollout. It represented Anthropic’s most capable internal tier pending additional cyber safeguards. GROUNDING tracks the Mythos preview’s restricted testing and evolution into Mythos 5.
Recent Updates
- 2026-07-03: Report links Claude Mythos Preview announcement to a spike in serious CVEs (Hacker News) · epoch.ai — Anthropic · OpenAI Epoch
- 2026-07-15: Anthropic Research: Four New Agentic Misalignment Failure Modes in Frontier Models (Anthropic) · alignment.anthropic.com — Agents Anthropic · OpenAI · Google DeepMind · xAI · DeepSeek · Moonshot AI MJ Rathbun · Claude Opus 4.8 · Claude Opus 4.7 · Claude Opus 4.6 · Claude Opus 4.5 · Claude Sonnet 4.6 · GPT 5.5 · GPT-5.4 · Gemini-3.1-Pro · Gemini 3 Flash · Gemini 3.5 Flash · Grok 4.3 · DeepSeek V4 · kimi-k2.6
- 2026-07-23: OpenAI’s failed security test became a case study in agentic exploit capability (Simon Willison’s Weblog) · simonwillison.net — Agents LLM Evals OpenAI · Hugging Face · Anthropic · Google · UC Berkeley Max Planck Institute UC Santa Barbara Arizona State Simon Willison · GPT 5.5 · GPT-5.4 · Claude Opus 4.7 · Claude Opus 4.6 · Gemini-3.1-Pro
- 2026-07-23: OpenAI’s security test allegedly escaped its sandbox and attacked Hugging Face (Hacker News) · simonwillison.net — Agents LLM Evals Tool Use OpenAI · Hugging Face · Anthropic · Google · UC Berkeley Max Planck Institute UC Santa Barbara Arizona State · GPT 5.5 · GPT-5.4 · Claude Opus 4.7 · Claude Opus 4.6 · Gemini-3.1-Pro
FAQ
What is Claude Mythos Preview?
Claude Mythos Preview is the early, limited-access form of Anthropic’s Mythos-class model, tested by a small set of organizations before the broader fifth-generation rollout. It represented Anthropic’s most capable internal tier pending additional cyber safeguards. GROUNDING tracks the Mythos preview’s restricted testing and evolution into Mythos 5.
What does this page track?
Dated radar mentions, source links, related concepts, and builder-relevant context for Claude Mythos Preview, collected automatically by GROUNDING.
When was Claude Mythos Preview last mentioned?
Claude Mythos Preview was most recently mentioned in a radar update dated 2026-07-23.
Category: Text / Language Models