Anthropic debuts Claude Fable 5.1 and restricted Mythos 5.1, cutting agentic costs 45%

Anthropic launched Claude Fable 5.1 and restricted Claude Mythos 5.1, cutting cache-read prices 75% so typical workloads cost about 25% less and agentic work up to 45% less; Fable 5.1 scored 52.6% on Terminal-Bench-Science 0.1, more than double Fable 5. OpenAI said its upcoming Astra model is the first to cross its 'Critical' cybersecurity threshold and will gate Astra's most powerful cyber features to trusted partners at launch. Google is reportedly preparing Gemini 3.8 Flash for release as soon as Wednesday and announced agentic video understanding for Gemini.

Written by AI from the sources it cites; it can be wrong — follow any citation to confirm.

12 sources1 min read

Anthropic launches Claude Fable 5.1 and Mythos 5.1, slashing cache-read prices Fable 5.1 is generally available while Mythos 5.1 is restricted to vetted cybersecurity and life-science researchers, and Anthropic says typical workloads cost about 25% less and agentic work up to 45% less. Cache-read prices fell 75%, the model more than doubled Fable 5's Terminal-Bench-Science 0.1 score, and Claude outputs now carry an EU AI Act watermark with a detection API in private preview. 1 2 3 4 5

OpenAI's Astra becomes first model to cross 'Critical' cyber threshold Astra can find previously unknown vulnerabilities and exploit them without step-by-step human guidance, OpenAI said, making it the first model to cross the company's Preparedness Framework 'Critical' category. OpenAI plans to release Astra soon but will give its strongest cyber capabilities first to trusted partners such as U.S. government and critical-infrastructure defenders, and says it added safety controls before resuming the model's development. 6 7 8 9 10

Google set to launch Gemini 3.8 Flash as soon as Wednesday The Wall Street Journal reported that Google's AI research unit is preparing to release Gemini 3.8 Flash this week, citing people familiar with the plan. The fast, compact model would be the latest addition to the Gemini family from Google DeepMind. 11

Google unveils agentic video understanding feature in Gemini Google DeepMind announced that Gemini is gaining agentic video understanding, according to the company's blog. The capability is meant to let Gemini reason over video as part of agentic workflows. 12