Simon Willison’s Weblog

Anthropic Release Notes: System Prompts (via) Anthropic now publish the system prompts for their user-facing chat-based LLM systems - Claude 3 Haiku, Claude 3 Opus and Claude 3.5 Sonnet - as part of their documentation, with a promise to update this to reflect future changes.

Currently covers just the initial release of the prompts, each of which is dated July 12th 2024.

Anthropic researcher Amanda Askell broke down their system prompt in detail back in March 2024. These new releases are a much appreciated extension of that transparency.

These prompts are always fascinating to read, because they can act a little bit like documentation that the providers never thought to publish elsewhere.

There are lots of interesting details in the Claude 3.5 Sonnet system prompt. Here's how they handle controversial topics:

If it is asked to assist with tasks involving the expression of views held by a significant number of people, Claude provides assistance with the task regardless of its own views. If asked about controversial topics, it tries to provide careful thoughts and clear information. It presents the requested information without explicitly saying that the topic is sensitive, and without claiming to be presenting objective facts.

Here's chain of thought "think step by step" processing baked into the system prompt itself:

When presented with a math problem, logic problem, or other problem benefiting from systematic thinking, Claude thinks through it step by step before giving its final answer.

Claude's face blindness is also part of the prompt, which makes me wonder if the API-accessed models might more capable of working with faces than I had previously thought:

Claude always responds as if it is completely face blind. If the shared image happens to contain a human face, Claude never identifies or names any humans in the image, nor does it imply that it recognizes the human. [...] If the user tells Claude who the individual is, Claude can discuss that named individual without ever confirming that it is the person in the image, identifying the person in the image, or implying it can use facial features to identify any unique individual. It should always reply as someone would if they were unable to recognize any humans from images.

It's always fun to see parts of these prompts that clearly hint at annoying behavior in the base model that they've tried to correct!

Claude responds directly to all human messages without unnecessary affirmations or filler phrases like “Certainly!”, “Of course!”, “Absolutely!”, “Great!”, “Sure!”, etc. Specifically, Claude avoids starting responses with the word “Certainly” in any way.

Anthropic note that these prompts are for their user-facing products only - they aren't used by the Claude models when accessed via their API.