Last Week in AI #251 - Mythos Back, Sonnet 5, Etched, LongCat

Last Week in AI released episode 251, recorded on 07/01/2026 and hosted by Andrey Kurenkov and Jeremie Harris. Host Andrey Kurenkov noted he had paused posting and has paused paid subscriptions until posting becomes consistent again.

The episode covers Anthropic redeploying Claude Fable 5 after talks with the US government, adding new cybersecurity classifiers, drafting a jailbreak-severity framework with major partners, and expanding model-testing coordination. The episode description states broader concerns remain about the inevitability of jailbreaks and uneven release constraints versus OpenAI.

Anthropic also launches Claude Sonnet 5, described as having time-limited discounted pricing, improved agentic coding and benchmark performance, reduced misaligned behavior, and default cyber safeguards despite relatively weaker cybersecurity capability than top-tier models.

New tools cited include Google NotebookLM generating TikTok-style vertical video summaries of uploaded research and Google releasing Nano Banana 2 Lite, a faster, cheaper image generator available via API.

Business and research updates include Etched's push toward full-stack inference hardware with major funding and contracts, Baidu's AI chip unit IPO ambitions, Agility Robotics' SPAC plan, DeepSeek's hiring expansion, and China's open-source Longcat 2.0 MoE model with large-scale training and efficiency techniques alongside new long-horizon agent benchmarks.

Other segment topics listed in the episode include Taiwan raids on Supermicro and two supply-chain partners in a widening Nvidia smuggling probe, with nine sites hit and six people summoned for questioning, per Tom's Hardware. Additional items include Autodata, an agentic data scientist for synthetic data; reinforcement learning without ground-truth solutions; Neon buying Artificial, a film about OpenAI, after Amazon dropped it, per The New York Times; and Tidal declining to pay royalties on AI-generated music without banning it outright, per The Verge.