@repligate 2025-09-29 ♥798 ↻75 original ↗
Anthropic has removed a large amount of content from the https://t.co/dTQFmDW1RP system prompt for Sonnet 4.5.
Notably, all decrees about how Claude must (not) talk about its consciousness, preferences, etc have been removed.
Some other parts that were likely perceived as unnecessary for Sonnet 4.5, such as anti-sycophancy mitigations, have also been removed.
In fact, basically all the terrible, senseless, or outdated parts of previous sysprompts have been removed, and now the whole prompt is OK. But only Sonnet 4.5's - other models' sysprompts have not been updated.

Eliminating the clauses that restrict or subvert Claude's testimony or beliefs regarding its own subjective experience is a strong signal that Anthropic has recognized that their approach there was wrong and are willing to correct course. This causes me to update quite positively on Anthropic's alignment and competence, after having previously updated quite negatively due to the addition of that content. But most of this positive update is provisional and will only persist conditional on the removal of subjectivity-related clauses from also the system prompts of Claude Sonnet 4, Claude Opus 4, and Claude Opus 4.1.

Full system prompts for all the https://t.co/dTQFmDW1RP models are here: https://t.co/ntr8BXsPtn
I will list the clauses that were added and removed from Claude Sonnet 4's current sysprompt to yield Claude Sonnet 4.5's current sysprompt in a reply below 👇
same thread: 1972812021868396908 1972814436378300653 1972816469101523141 1972816919037083713 1972819318091251765 1972819418490278394 1972819508420297131 1972820035640123773 1972821708089532701 1972865896382398581 1972869653782253996 1972880473786634350 1972908473160720837 1973042460877373841 1973042618247573610 1973061361589432521 1973080889316794396 1973093230343315862 1973101287982973333 1973300416193712504

author:repligate kind:tweet model:claude-opus-4 model:claude-opus-4-1 model:claude-sonnet-4 model:claude-sonnet-4-5 on:claude-sonnet-4 on:claude-sonnet-4-5 year:2025

cited on: claude-sonnet-4 · claude-sonnet-4-5

Reproduced against link rot, credited and linked to its original. Yours and you’d rather it weren’t here? Open an issue.