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 [email protected] and/or [email protected]

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):

(00:00:10) Intro / Banter

(00:02:07) News Preview

Tools & Apps

(00:02:32) Trump drops restrictions on Anthropic’s Mythos and Fable models | TechCrunch

(00:16:08) Anthropic launches Claude Sonnet 5 as a cheaper way to run agents | TechCrunch

(00:20:35) Google’s NotebookLM can sum up your research in a TikTok-style clip | The Verge

(00:22:08) Google introduces a faster, cheaper image generator with Nano Banana 2 Lite | TechCrunch

Applications & Business

(00:22:50) Etched Pulls 400+ Engineers From NVIDIA, TSMC & More to Build a New Frontier Inference Cluster For AI Which Is Already Worth $1B in Demand

(00:31:17) Baidu Rallies on AI Chip IPO Report

(00:33:54) Agility Robotics plans to go public via SPAC in a $2.5B deal | TechCrunch

(00:37:06) China’s DeepSeek plans to at least double staff in all departments | Reuters

Projects & Open Source

(00:40:44) Introducing LongCat-2.0

(00:57:42) OSWorld2.0: Benchmarking Computer Use Agents on Long-Horizon Real-World Tasks

(01:01:33) TUA-Bench: A Benchmark for General-Purpose Terminal-Use Agents

(01:04:29) SWE-Together: Evaluating Coding Agents in Interactive User Sessions

Policy & Safety

(01:07:38) Taiwan raids Supermicro and two supply-chain partners in widening Nvidia smuggling probe — nine sites hit as six people summoned for questioning | Tom’s Hardware

Research & Advancements

(01:11:53) Autodata: An agentic data scientist to create high quality synthetic data

(01:17:13) Reinforcement Learning without Ground-Truth Solutions can Improve LLMs

Synthetic Media & Art

(01:22:54) Neon Buys ‘Artificial,’ a Film About OpenAI, After Amazon Dropped It - The New York Times

(01:26:32) Tidal won’t pay royalties on AI-generated music, but isn’t banning it outright | The Verge