Simon Willison’s Weblog

Long context prompting for Claude 2.1. Claude 2.1 has a 200,000 token context, enough for around 500 pages of text. Convincing it to answer a question based on a single sentence buried deep within that content can be difficult, but Anthropic found that adding “Assistant: Here is the most relevant sentence in the context:” to the end of the prompt was enough to raise Claude 2.1’s score from 27% to 98% on their evaluation. # 6th December 2023, 11:44 pm

Claude: How to use system prompts. Documentation for the new system prompt support added in Claude 2.1. The design surprises me a little: the system prompt is just the text that comes before the first instance of the text “Human: ...”—but Anthropic promise that instructions in that section of the prompt will be treated differently and followed more closely than any instructions that follow.

This whole page of documentation is giving me some pretty serious prompt injection red flags to be honest. Anthropic’s recommended way of using their models is entirely based around concatenating together strings of text using special delimiter phrases.

I’ll give it points for honesty though. OpenAI use JSON to field different parts of the prompt, but under the hood they’re all concatenated together with special tokens into a single token stream. # 22nd November 2023, 4:31 am

Introducing Claude 2.1. Anthropic’s Claude used to have the longest token context of any of the major models: 100,000 tokens, which is about 300 pages. Then GPT-4 Turbo came out with 128,000 tokens and Claude lost one of its key differentiators.

Claude is back! Version 2.1, announced today, bumps the token limit up to 200,000—and also adds support for OpenAI-style system prompts, a feature I’ve been really missing.

They also announced tool use, but that’s only available for a very limited set of partners to preview at the moment. # 22nd November 2023, 4:28 am

Before Altman’s Ouster, OpenAI’s Board Was Divided and Feuding. This is the first piece of reporting I’ve seen on the OpenAI situation which has offered a glimmer of an explanation as to what happened.

It sounds like the board had been fighting about things for over a year—notably including who should replace departed members, which is how they’d shrunk down to just six people.

There’s also an interesting detail in here about the formation of Anthropic:

“Mr. Sutskever’s frustration with Mr. Altman echoed what had happened in 2021 when another senior A.I. scientist left OpenAI to form the company Anthropic. That scientist and other researchers went to the board to try to push Mr. Altman out. After they failed, they gave up and departed, according to three people familiar with the attempt to push Mr. Altman out.” # 22nd November 2023, 12:31 am

Decomposing Language Models Into Understandable Components. Anthropic appear to have made a major breakthrough with respect to the interpretability of Large Language Models:

“[...] we outline evidence that there are better units of analysis than individual neurons, and we have built machinery that lets us find these units in small transformer models. These units, called features, correspond to patterns (linear combinations) of neuron activations. This provides a path to breaking down complex neural networks into parts we can understand” # 8th October 2023, 3:43 pm

claude.ai. Anthropic’s new Claude 2 model is available to use online, and it has a 100k token context window and the ability to upload files to it—I tried uploading a text file with 34,000 tokens in it (according to my ttok CLI tool, counting using the GPT-3.5 tokenizer) and it gave me a workable summary. # 12th July 2023, 4:39 pm