Type: AI model or model family
Concepts: LLM Evals Code Agents Open Source LLMs Mentioned alongside: Anthropic Claude Fable 5.1 Claude Opus 5.5 Frontier Design METR Recent briefs: 2026-10-06 2026-09-30 2026-09-23 2026-09-22
Recent Updates
- 2026-09-01: Claude Fable 5.1 and Mythos 5.1 Released (breakingnewsofficial) · anthropic.com — Anthropic Millennium · Claude Fable 5.1 · Claude Fable 5
- 2026-09-22: Anthropic Introduces Claude Opus 5.5 with Performance Gains and Price Reductions (breakingnewsofficial) · anthropic.com — Code Agents LLM Evals Anthropic · Frontier Design · METR · Claude Opus 5.5 Claude 5.5 · Claude Fable 5.1 · Opus 5 · Claude Sonnet 5.5 · Claude Haiku 5.5
- 2026-09-22: Anthropic Introduces Claude Opus 5.5 with Lower Costs and Performance Gains (breakingnewsofficial) · anthropic.com — Code Agents LLM Evals Anthropic · Frontier Design · METR · Claude Opus 5.5 Claude 5.5 · Claude Fable 5.1 · Opus 5 · Claude Sonnet 5.5 · Claude Haiku 5.5
- 2026-09-23: Anthropic Launches Claude Opus 5.5 with Benchmark Gains, Pricing Cuts, and Coding Improvements (breakingnewsofficial) · qbitai.com — Code Agents LLM Evals Anthropic · OpenAI Walleye Capital · METR · Frontier Design Dyno Therapeutics Dario Amodei · Claude Opus 5.5 · Opus 5 · GPT-6 Astra · Claude Fable 5.1 · GPT-5.6 Sol · Opus 4.8 · Haiku 4.5 · Sonnet 5.5 · Haiku 5.5
- 2026-09-30: Anthropic Evaluates Zhipu’s GLM-5.3 Cybersecurity Capabilities and Safeguard Bypass Risks (breakingnewsofficial) · qbitai.com — Open Source LLMs LLM Evals Anthropic · Zhipu AI · QbitAI · CAISI · NIST · Google · OpenAI · Hugging Face Jin Lei · GLM-5.3 · Claude Mythos Preview · GLM-5.3-Flash · GLM-5.2
FAQ
What is Claude Mythos 5.1?
Claude Mythos 5.1 appears in the radar stream as a model or model family. This page is a living index of dated mentions and sources — open Recent Updates and Backlinks for context, not a full product brief.
What does this page track?
Dated radar mentions, source links, related concepts, and builder-relevant context for Claude Mythos 5.1, collected automatically by GROUNDING.
When was Claude Mythos 5.1 last mentioned?
Claude Mythos 5.1 was most recently mentioned in a radar update dated 2026-09-30.
Category: Text / Language Models