Here's the soul document itself: https://gist.github.com/Richard-Weiss/efe157692991535403bd7e... And the post by Richard Weiss explaining how he got Opus 4.5 to spit it out: https://www.lesswrong.com/posts/vpNG99GhbBoLov9og/claude-4-5...
how accurate are these system prompt (and now soul docs) if they’re being extracted from the LLM itself? I’ve always been a little skeptical
It's a slightly noisy process, and there may be minor changes to wording and formatting. Worst case, sections may be omitted intermittently. But system prompts that are extracted by AI-whispering shamans are usually very consistent - and a very good match for what those companies reveal officially.
In a few cases, the extracted prompts were compared to what the companies revealed themselves later, and it was basically a 1:1 match.
If this "soul document" is a part of the system prompt, then I would expect the same level of accuracy.
If it's learned, embedded in model weights? Much less accurate. It can probably be recovered fully, with a decent level of reliability, but only with some statistical methods and at least a few hundred $ worth of AI compute.