Claude Code is steganographically marking requests

Post by pishpash » Tue, Jun 30, 2026, 5:40 PM UTC

pmxi wrote: post #80

sebastiennight wrote: post #50

Can somebody clarify for me - if ANTHROPIC_BASE_URL is set to a different provider... then isn't this "marked" system prompt being sent to that provider's API rather than Anthropic's? I understand how this can be useful to Anthropic if the 3rd-party is acting as a proxy (because they end up hitting the Claude API with the marked prompt), but it looks like requests where "hostname contains deepseek" would never be sen…

This catches Claude resellers. Meaning companies who proxy Claude traffic for users in, say, China. https://www.chinatalk.media/p/how-to-buy-cheap-claude-tokens...

Post by zulban » Tue, Jun 30, 2026, 5:41 PM UTC

llelouch wrote: post #97

fny wrote: post #45

This was already discovered during the source map leak. > This is not a malicious feature, but it is a weird choice for a developer tool that asks for trust. They already tell you they scan for malicious prompts, and they have no ZDR guarantees for consumers. Why do signatures like this matter at all?

There has been an anti anthropic propaganda push by bad actors across social media sites especially Reddit and twitter. This started a few months ago when anthropic started beating openai.

Post by SepiaSapient » Tue, Jun 30, 2026, 5:46 PM UTC

hn_throwaway_99 wrote: post #157

skeptic_ai wrote: post #118

Earlier quoted context omitted.

It’s even more funny how this blew in their faces. They even advertised pretty much all providers on hackernews home page. Here is in case you missed in the article ‘’’ cn baidu.com alibaba-inc.com alipay.com antgroup-inc.cn bytedance.net kuaishou.com xiaohongshu.com jd.com bilibili.co iflytek.com stepfun-inc.com moonshot.ai anyrouter.top claude-code-hub.app claude-opus.top openclaude.me proxyai.com yunwu.ai zenmux.a…

You have an odd definition of "blew up in their faces". What, do you somehow think your average Claude Code user on HN is going to think "Oh wow, I'm sure I'll get a much better experience if instead of going to the standard Anthropic Claude API endpoint I go through xiaohongshu.com."

Post by Philip-J-Fry » Tue, Jun 30, 2026, 5:49 PM UTC

meowface wrote: post #92

Value judgment aside: I am a bit surprised at how sloppily they did this. I think they could've achieved the same effect while decreasing the odds of detection via reverse engineering. (This field is known as "underhanded code", coined by the Underhanded C contest: https://www.underhanded-c.org . It's a little-known "art"; little-known for probably self-explanatory reasons. There are much cleverer ways of achieving o…

Post by mcmcmc » Tue, Jun 30, 2026, 5:51 PM UTC

overgard wrote: post #182

meowface wrote: post #92

Value judgment aside: I am a bit surprised at how sloppily they did this. I think they could've achieved the same effect while decreasing the odds of detection via reverse engineering. (This field is known as "underhanded code", coined by the Underhanded C contest: https://www.underhanded-c.org . It's a little-known "art"; little-known for probably self-explanatory reasons. There are much cleverer ways of achieving o…

Well considering how Claude is vibe coded, I can't say I'm really surprised by sloppiness at all. I've been moving more towards Codex and OpenCode not because the the anthropic models are bad, but because Claude seems to break something new and annoying every day.