TLDR AI 2025-12-01

Go under the hood of Optimizely Opal.

CLAUDE 4.5 OPUS' SOUL DOCUMENT

There appears to be a document in the character training for Claude compressed within Claude's weights. While it is possible for the model to hallucinate the text, it appears to be real. This post details how the document was extracted. The full output of Claude's Soul Document is available in the post.

OPENAI MAY DEPLOY ADS SOON

A recent update to the ChatGPT Android app included references to an “ads feature” with “search ads” and “bazaar content”.

DATABRICKS REPORTEDLY IN TALKS TO RAISE $5B AT $134B VALUATION

Databricks is reportedly in talks to raise $5 billion at a $134 billion valuation. The company has resisted pressure to go public, but an IPO would likely be well-received. Databricks has more than 20,000 customers, including OpenAI, Block, Shell, and Toyota. Its platform offers tools that support the full lifecycle of AI development, including feature engineering, model training, evaluation, and deployment.

HOW PROMPT CACHING WORKS

Prompt caching works per-content, not per-conversation. Prefix caching works at the token level, not the request level, which is why it works across requests. Any change in the prefix breaks the entire hash chain.

ARE WE IN A GPT-4-STYLE LEAP THAT EVALS CAN'T SEE?

Chat is a terrible way to evaluate models. GPT-4 was so significantly better at answering questions that it was an obvious step forward. The industry needs to add more types of benchmarking. Models are currently being evaluated like students in an exam, but that's not representative of how the world works.

the whole team. Read the blog

WHAT MAKES A GREAT CHATGPT APP

The biggest mistake developers make is trying to port entire products into ChatGPT when they should instead expose a few powerful capabilities the model can orchestrate mid-conversation. Devs should organize around giving ChatGPT new data it can't access ("know"), enable real actions like booking appointments or playing games ("do"), and present information through richer UI than text walls ("show").

CONTEXT PLUMBING

Context is always changing, as it is dynamic. The context is not always where the AI runs. To make an agent run really well, you need to move the context to where it needs to be. Agents shouldn't have to look up context for every single query, because that's slow. Engineers need to build pipes that continuously flow potential context from where it is created to where it is going to be used.

EMBODIED COGNITION BENCHMARKING

ENACT is a benchmark for evaluating embodied cognition using egocentric world modeling.

IT'S HARD TO FEEL THE AGI

Some of the most accomplished minds in AI are beginning to revise their projections for the near future. This may not be entirely unexpected for those who follow the field. LLMs and other generative models have undoubtedly made many tangible achievements. Discovering their limits remains a challenging task that could be lost if industry climate drops to a new 'AI winter'.

VIBE PROVING IS HERE

An AI model just proved Erdos Problem #124 in Lean by itself. The problem has been open for nearly 30 years. The achievement shows how mathematical superintelligence is getting closer. The technology will change and dramatically accelerate progress in mathematics and all dependent fields.

AI ADOPTION RATES STARTING TO FLATTEN OUT

This post contains charts that show how AI adoption rates are flattening out across all firm sizes.

THE THINKING GAME

The Thinking Game is a documentary that covers the pivotal moments over five years at DeepMind, an AI company founded by Demis Hassabis.

INSIDE GEMINI 3 WITH SUNDAR PICHAI (27 MINUTE VIDEO)

Google CEO Sundar Pichai reflects on the company's long-term AI strategy, the evolution of Gemini 3, and future bets like quantum computing in a conversation on the Google AI podcast.