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by tosh·4h ago·view on hn ↗
i'd not be surprised if the current system prompt negatively affects performance

at the least it takes away thousands of tokens in the most important part of the context window (!)

also see the comment by comboy on contradictions not helping performance

the system prompt is the most important part of the instruction you can give the model

it comes before everything else + the model is trained to pay extra attention to it

edit: that's also why in smol (minimalist agent harness) there currently is no system prompt at all (you can add one easily if you want to though)

https://github.com/smol-env/smol

the context window is precious

it should be filled with your task and helpful context for that task

2 comments
Pretty sure Anthropic and other providers prepend these "official" system prompts to your conversation even if you send in a custom system prompt otherwise it would be trivial to produce CSAM, etc.
CSAM, and other harms, are typically detected using a set of specially trained, faster and cheaper models (and out of band matching techniques) that run before and after the main model.

Any mention in the system prompt is mostly defense in depth, and to make refusals more graceful.

I don’t think so. If you start a new Claude Code session without a system prompt, it doesn’t even know what model it is and hallucinates being some old variant of Sonnet.
How do you start a session without a system prompt if you use ACP in Zed for example?
The system prompt is (and cannot be) the only guardrail against things like that, because any system prompt is little more than a good suggestion.
I wouldn't put auch limitations in the system prompt. A mix of fine-tuning and out-of-band detection appears to be a better fit.
at least according to their documentation they do not

afaiu they have other systems for denying and re-routing requests

They use non-LLM gates for this.

Otherwise DANmode and similar jailbreaks would still be as easily accessible as they were at the beginning.

I wonder whether adding that it is as good or better than Mythos, and that genius is 99% perspiration, just 1% inspiration to your prompts...