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Comment by boorang | Hacker News Reader

FYI you can modify the system prompt using mitmproxy. Just ask your agent to walk you through it. Anthropic system prompts are gnarly and geared towards the lowest common denominator.

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> FYI you can modify the system prompt using mitmproxy

The system prompt is injected into your context on the server side.

there is literally a --system-prompt flag for claude code. In my mitmproxy experiments using that flag appended to the existing system prompt rather than replacing it. So I had to create a little helper to strip the system prompt sent over the wire and add my own.

here is a collection of public system prompts from claude code: https://github.com/Piebald-AI/claude-code-system-prompts

Use --system-prompt-file, it will replace the whole system prompt (https://code.claude.com/docs/en/cli-reference ). You'll have to use a shell alias or function or something to always append this flag when calling Claude Code but you don't need any MitM shenanigans. Then use "/context all" to see what else is sent (here I would recommend MitM'ing since Claude Code won't show the exact tools and text), there are a lot of tools no one needs and they are bloating the context, you can deny these in the settings.json (there is also a list here: https://code.claude.com/docs/en/tools-reference ). Also set "disableClaudeAiConnectors" to false to remove even more bloat.

I tried both --system-prompt and --system-prompt-file. they both appended when i tried about 6 months ago and watched the traffic. Yes I cleanup all those tools etc.

--system-prompt-file replaces the prompt, I use it myself and the docs state it, too.

Did you verify with tcpdump/Wireshark?

thinking you can control what happens to some strings you send over the network.

...the absolute state of the token maximizers.

Claude, think for me. Make no mistakes.

too late to edit, but i wanted to apologize for my snarky tone.

my comment was to show incredulity that people do the equivalent of pressing f12 on the browser and submitting a form bypassing the JavaScript validation. you cannot really think the backed will not have the same logic you just bypassed.. but now i realized we're talking about Ai companies so i might be the idiot after all.

please accept my apologies.

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