#243 - GPT 5.5, DeepSeek V4, AI safety sabotage

Our 243rd episode with a summary and discussion of last week's big AI news!

Recorded on 04/29/2026

Hosted by Andrey Kurenkov and Jeremie Harris

Feel free to email us your questions and feedback at [email protected] and/or [email protected]

Read out our text newsletter and comment on the podcast at https://lastweekin.ai/

In this episode:

• OpenAI released GPT-5.5 with strong coding-oriented improvements, a system card discussing chain-of-thought monitorability and misalignment testing, higher pricing than GPT-5.4, and notable quirks like a system-prompt warning about “goblins.”
• xAI launched Grok Voice Think Fast 1.0, claiming large benchmark leads for real-time voice agents and reporting major Starlink customer-support automation and sales conversion impact.
• DeepSeek open-sourced DeepSeek V4 (Pro and Flash) featuring MoE scaling and 1M-token context via hybrid/compressed attention changes, while Tencent released Hunyuan 3 preview with weaker benchmark performance; a new long-horizon agent benchmark (Clawmark) shows low task success rates.
• Major business, legal, and policy updates include Google’s planned up-to-$40B investment and 5GW compute commitment to Anthropic, Meta’s AWS Gravitron deal and China blocking Meta’s Manus acquisition, a revamped OpenAI–Microsoft agreement, ongoing Musk–OpenAI trial developments, and new safety/security research on sabotage, document degradation under delegation, and bit-flip attacks.

Timestamps:

• (00:00:10) Intro / Banter
• (00:02:00) News Preview
• (00:02:26) Response to listener comments
• (00:02:55) Sponsors

• Tools & Apps
• (00:05:55) OpenAI Unveils Its New, More Powerful GPT-5.5 Model - The New York Times
• (00:23:33) xAI Launches grok-voice-think-fast-1.0: Topping τ-voice Bench at 67.3%, Outperforming Gemini, GPT Realtime, and More - MarkTechPost
• (00:29:00) Claude can now plug directly into Photoshop, Blender, and Ableton | The Verge

• Projects & Open Source
• (00:29:38) China's DeepSeek releases preview of long-awaited V4 model as AI race intensifies
• (00:47:05) Tencent Unveils Hy3 preview; Model Enhances Agent Capabilities and Real-World Usability - Tencent 腾讯
• (00:50:14) ClawMark: A Living-World Benchmark for Multi-Turn, Multi-Day, Multimodal Coworker Agents

• Applications & Business
• (00:53:03) Google Plans to Invest Up to $40 Billion in Anthropic
• (00:56:26) Meta will use hundreds of thousands of AWS Graviton chips
• (00:59:51) China blocks Meta's $2 billion takeover of AI startup Manus
• (01:01:45) OpenAI shakes up partnership with Microsoft, capping revenue share payments
• (01:07:13) Elon Musk Testifies of AI Risk at Trial, Says OpenAI Tried to ‘Steal’ a Charity - WSJ
• (01:11:50) Judge rejects DOJ bid to delay Anthropic appeal in Pentagon dispute
• (01:14:42) Google’s Gemini can now run on a single air-gapped server — and vanish when you pull the plug
• (01:19:07) DeepMind's David Silver just raised $1.1B to build an AI that learns without human data | TechCrunch

• Policy & Safety
• (01:22:47) Evaluating whether AI models would sabotage AI safety research
• (01:28:59) LLMs Corrupt Your Documents When You Delegate
• (01:32:50) Temporal Sparse Autoencoders: Leveraging the Sequential Nature of Language for Interpretability
• (01:39:53) Memorandum on Adversarial Distillation of American AI Models
• (01:41:41) Teen boys are dating their AI chatbots—and experts warn it could kill their careers | Fortune
• (01:43:57) Announcing the Anthropic Economic Index Survey
• (01:45:21) Scoop: CISA lacks access to Anthropic's Mythos

• Synthetic Media & Art
• (01:48:03) Taylor Swift Files to Trademark Voice and Likeness to Protect Against AI Misuse

• Research & Advancements
• (01:49:15) Maximal Brain Damage Without Data or Optimization: Disrupting Neural Networks via Sign-Bit Flips

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