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

Note from Last Week in AI (Andrey): I’m back! And i’m sorry for putting the substack on a silent pause, work got a bit too overwhelming so I fell behind on this. I’ll do my best to resume normal posting, starting with catching up on podcast episodes missing from here (which are not last week… but I guess I should post them still, sorry for the spam!)

I’ve also paused paid subscriptions until I can get back to consistent posting. Apologies for the flakiness, and thanks for being a subscriber!

Our 251st episode with a summary and discussion of last week’s big AI news!

Recorded on 07/01/2026

Hosted by Andrey Kurenkov and Jeremie Harris

Feel free to email us your questions and feedback at andreyvkurenkov@gmail.com and/or hello@gladstone.ai

In this episode:

Anthropic redeploys 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; broader concerns remain about the inevitability of jailbreaks and uneven release constraints versus OpenAI.
Anthropic launches Claude Sonnet 5 with 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 and apps 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 span 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 notable large-scale training and efficiency techniques alongside new long-horizon agent benchmarks.

Timestamps (note – these don’t take into account dynamically inserted ads and therefore may be off by a couple of minutes):