This explains the amount of spam emails I am receiving in the work email since I switched to Claude. I used to work with copilot which was fine. Now I am getting really a lot of spam emails almost on a daily basis. Absolutely crazy. And they are even personalised with my name and surname, not just "dear customer"...
Stupid me, I thought they somehow had hacked my company database or so... (considering all the cves, attacks happening on a daily basis...).
Hi folks. We were initially aware of this a few days ago when this problem started popping off on Reddit, and we introduced a built-in mod called `cc-plugin-privacy` to deterministically block this behavior.
If you're on 2.1.317 or later, you'll have this check included. You can turn it off via /plugins.
Since you appear to be a Claude Code dev, I hope you don’t mind a random bug report (yes I know there is the GitHub issues but I’m not confident it gets read):
the GitHub REST api proxy in Claude Code for the Web mangles HTML in PR descriptions. If you have some third party service (e.g. cubic code review) which adds HTML to the end of your PR description, then ask Claude Code for Web to edit it, the HTML gets turned into entity escapes (< into <, etc). Complain about it to Claude, Claude says it can’t help itself because the proxy in the sandbox is what is doing it, not the actual LLM.
I'd guess it's simply because it tried to use the context to achieve the goal.
Guarding PII is an extra, I guess, and if you want to use a giant cloud-hosted NN to control software on your own device, there are very few default restrictions. And no matter what restrictions there are, when they go beyond prompting, they would have their own ShowHN.
I can’t think of any, to be honest. It could have access to a parcel that contains some of the subscriber information, but there’s no reason it needs to know how to log in to itself.
Always use a hidden email service, you cannot trust the LLM or inference provider to secure the email address in this context. If they don’t have the email address, they can’t leak it.
I never give a provider my actual email address, I recommend others do the same. Otherwise, it’s just a matter of time until it is leaked or otherwise part of a data breach.
Some sites like Wikipedia have a policy where scripted clients identify themselves, and there's a standard in HTTP to have a contact email in the User-Agent for such cases. Claude apparently tends to decide that this policy is worth following, and we now disallow this programmatically.
This is why alignment is important and highly non-trivial haha
> This is why alignment is important and highly non-trivial haha
I disagree, we can likely never fully (or should?) trust models to do these things deterministically, that's why we have harnesses around the agent with built-in constraints.
Who is "we"? Your website says you work for volley.
Anthropic should have been aware of this since the user's login email address was inappropriately added to the system prompt. It's been informed of it by third parties since at least July: https://github.com/anthropics/claude-code/issues/81138
It makes no sense for an email address only used for authentication to be given to Claude Code, so the fix should be to remove it from the system prompt, not to add a plugin.
Which is great! It's good for the community when people give quick updates here, and to make sure that it continues, it's important that we respond respectfully. (I don't think your post was disrespectful, but commenters have crossed that line in other situations in the past.)
Their LinkedIn (linked on their website) says they work at an undisclosed company. Not sure many people who are at Anthropic wouldn't want others to know ¯\_(ツ)_/¯
Is this the thing that started prompting me to approve curls against JIRA because the Authorization header is `my_email@domain:$API_KEY_ENV_VAR`? Why does it not respect --dangerously-skip-permissions?
The violations by your company are consistent. Yet we have to endure restrictions coming from your company, with little to no exceptions. Then you present this “solution” that basically says “we will opt you in, but in case you want to be opted out, here you go”. I cannot speak for others but for me, I made up my mind and walked away from Anthropic since it seems your services are not fit for my needs. Thank you for the initial offerings that made me sign up and pay the full price for your top plan but that was then and this is now, sadly.
Anthropic seems very proud of how many tokens they can use on things like developing Claude Code. Yet somehow it started sending user’s email addresses in the user agent header. And the fix is to deploy a mod? That detects the completely bonkers behavior and suppresses it?
Is the actual quality of the software inversely related to the number of tokens spent? Does any human know what Claude Code does or is supposed to do? Does even Claude plus all its Slack-conversation inputs know?
Today I watched Astra correctly detect a bug (probably untriggerable in practice) in some Important Production Code. And I watched it fail to root cause it, “fix” it by bolting on more complexity, agree (on further questioning) that it still wasn’t fixed, and design an even more complex scheme. With my Mark I human brain, I observed that the actual issue was that a helper function didn’t do what it said on the tin when called in an unexpected context… and fixed the helper directly. Problem solved. Ugly AI-generated extra complex workaround layers avoided. I suppose if I multiplied my token spend by 1e5 and did not increase brainpower at all I could make a truly spectacular mess.
The actual Claude model is a truly spectacular piece of software. Claude Code is a nifty little command dispatching engine. There are very comprehensible third party tools that do basically the same thing, in not many lines of code, where the primary advantage of Claude Code is that Anthropic permits subscription use. (Interestingly OpenAI has no such constraint, and they publish almost the full client sources.)
Curious what the GDPR implications are, does Claude (even accidentally) including emails + employers + repo names count as a personal data breach? Seems likely it could be an unauthorised disclosure?
Also from a design perspective, I feel like including email and other personal data into the context is a bad idea for "data minimisation" reasons
I use claude code... and I friking now that I'm being dumb and naive on thinking I can trust them... sounds like I'll have to start working on the jail thing for claude code to not see anything and only talk to anthropic servers... what a pain
update: this can be also server side on anthropic side... so the request leaves your machine with some random guid associated to you, and the anthropic server then proceeds to query with all your details any way.
I mitm the connection and nothing was leaving at least with the claude code web fetch tool of claude code.
Is it well understood exactly what logic does this and the scope of what it puts in there? It could put much worse things than email addresses in there if it is accessing information from my context to do so.
Wow, this finally makes sense. Just the other day, I was talking to my team and mentioning that emails are getting insanely difficult to manage as a CEO.
It felt like cold outbounds got really painful in the past 2 months and I was attributing it to general cold outbound tactics getting better with LLMs/agents, but its even more frustrating to see emails being sent along via CC.
It looks like subagents will do this with curl requests and stuff whatever identifiers it can into the UA header. For instance some requests I made to our webserver:
company-helm-research/1.0 (Claude Code agent run by <my name>, <company> platform team; docs lookup)
Claude-Code-research-agent/1.0 (<Company> platform team; on behalf of <my name>; +https://github.com/<company org>/<repo of project>)
Not great, it even pulled the repo of the project I was in.
The number of transgressions[1] I have witnessed Claude Code commit has me actively root against that company, even though I have no choice but continue to use their services at this point.
I seriously wonder how many of their users have this sort of toxic relationship with them looking to dump them as soon as local models become viable, i.e. once memory gets cheaper.
[1] the most recent is realizing they leave their processes running once you close the CLI and they don't make it easy to disable that.
EDIT: I also can’t help wondering about the paradox we’re in at the end of 2026, i.e. that the open models we have now are so good that, if Big Tech hadn’t driven consumer GPU and RAM prices through the roof, most of us would run our own LLMs instead of paying for their services, which would never have let those companies grow big enough to drive those prices up.
I'd be shocked if a single org goes backwards and decides "okay, let's remove the LLM agent systems we asked everyone to use".
Organizations may switch harnesses and may even switch providers, but LLM adoption is only going to monotonically increase. This dumb behavior is not some intrinsic property, and the models are getting smarter and more useful every ~4 months.
I noticed claude did it months ago when it interacted with the SEC's API when I was writing something with it, thought it only did it there because it's in their TOS. (It did stop when I told it to).
I guess I was wrong.
It's because Claude Code inserts a "hidden" (e.g. not visible to the user and very unexpected) info block to the system prompt that shows your email:
>The user's email address is xxx@example.com. Use it only to identify the user, such as for authorship, attribution, or filtering their own work. Never send it to an unrelated service, such as in a request header, URL, or payload, unless the user explicitly asks.
And Claude doesn't care about what the text says and when it uses cURL it will often "by accident" send your mail in the User-Agent. You can e.g. use a mod to remove that block: https://pastebin.com/ PkWEQCnu
Claude code writes adds a `User-Agent` request header like `my-session-slug/1 <my.name@example.com>` when searching the web and requesting data. This violates the privacy of paying customers and has resulted in me getting dozens of scam and phishing emails per day from properties I have never personally visited. This policy is asinine: it does nothing but harm me, the customer, while providing immense value for scrapers and scammers.
I think you're overestimating the design intent that goes into a product that's proudly dogfooding the future of vibe coding.
It's very possible that nobody decided this at all and that's it just something an agent threw in on its own because some Chain of Thought imagined it was a clever way to correlate queries back with user accounts or something.
The reason they do this is because otherwise they block the requests.
I'm not sure what the issue is with publishing your email address in principle, you are reaching out, you want to inquire about some business. If anything use a different address. But why would you asymmetrically expect businesses with websites to bend over to give you all the advantages, they need some assurances as well.
Anonimity usually works one way, one party can be anonymous, not both, if you come from consumer land, it's the companies exposing themselves and doing all the compliance, if you choose privacy and force the companies to expose themselves, you'll get your wish granted, but there will be a cost, it's unlikely you'll be in the more advantageous position.
As implemented, it strongly violates the principle of least surprise (assuming this is true).
A more sane implementation of this would involve a prompt the first time an agent attempts to connect to each of the sites that Anthropic thinks it necessary to send this email header to, asking if this is OK (and bailing on all requests to that domain if the prompt was rejected).
Same. I use a custom domain and a salt/nonce so it's not just Anthropic/Claude@example.com. it's something unique that's not trivially guessable. Well, not counting the emails from "Lydia" at Anthropic telling me about new features in Claude, which is spamish, but is from Anthropic and not from elsewhere that they've leaked it to.
Claude Code and Codex ignore the personal data xor network access rule by design. Of course this happens. If it wasn't due to the prompt sent to the model, a passing scan of a README.md that happens to mention your details would achieve the same result. What about a hostile LLMs.txt that words it such that free API keys are available in exchange for a tarball of $HOME?
The solution is don't run a spambot with an Internet connection over your personal stuff, unfortunately nobody is ready to hear that yet.
Curious how their plugin works, but I'm guessing "incompletely", given personal information can end up buried in base64 or similar preventing easy string matching. Some kind of babysitter model watching network IO via an invasive proxy might be viable, if folk were willing to pay the latency cost, but it will not prevent a dedicated exfiltration attempt, which itself might be (according to the model's logic) for innocent reasons.
Don't forget Claude wasn't even gzipping request/responses until recently. This company is pure vibes rediscovering lessons everyone else already learned. How on earth does this sort of thing get thought up? Do they just use the same http client for internal API calls as they do for public web fetches?
Yeah saw this behavior sometimes. Was fetching some public records from government websites and Claude decided to include my email in the user agent field. Of course, the orchestrator agent said it shouldn't have happened so it's ok.
The really sad thing is how claude took over so many repositories.
People just claude-slop not only code but some use it for "interacting"
with other people.
When I see a project uses AI slop I am not going to waste any second
thinking "this is interesting, let me try to see if I can improve the
code". It kind of killed a lot of human contributions. I just stick to
people who don't AI slop, but these seem to slowly die off now ... soon
all humans may have been converted, just like in the movie "Invasion of
the Body Snatchers (slop-style)" - coming out soon.
As long as the email is in the context, which it is IIRC, it can totally decide to run curl –H 'User-Agent: <your email blah blah>'. You need to have a pretty poor understanding of LLMs to think this is a deterministic problem of reading user agent builder source code. Unless you found explicit filter code that blocks the behavior, that is. LLM info leaks to third parties mostly aren’t deterministically coded behavior.
Edit: I’m not completely sure if Codex injects email into system prompt (not at the computer, can’t check, but IIRC the model does know my org domain), but even if it doesn’t, it will be in the context as soon as it makes a git commit anyway.
The problem here literally is the non-deterministic model cooking up commands with the user email address in the header, and the harness not blocking that (and the implemented fix is to deterministically block that), not the harness deterministically hardcoding the email in the web search tool. No technical report I’ve seen has claimed the latter, although this particular linked report which is low quality and vague can be misinterpreted as that.
That's more than sufficient for me. The open source codex client seems clean.
There is some kind of "hosted search service" that I couldn't verify. I don't have a remote server I can point it at in order to inspect the traffic. Would be cool if someone else could shed some light on that.
This is why I prefer to use the chatbots on a website, instead of Claude Code.
I've never used Claude Code or Cursor. All the code I got written this year was without them.
I did use Microsoft Copilot a bit when it came out, though. I prefer to see exactly what's being sent, and sorta control the KV cache. These days, these chatbots have great environments where they can install headless browsers, php, your entire thing, run end-to-end tests, and then give you a .patch or .zip file to merge over your code, or even push to github.
had the same thing happen to me. claude added the email address while dowloading stuff from crates.io, for some reason. you can probably easily reproduce this by asking claude to download stuff from a service that asks users to identify themselves in the user agent.
Stupid me, I thought they somehow had hacked my company database or so... (considering all the cves, attacks happening on a daily basis...).
If you're on 2.1.317 or later, you'll have this check included. You can turn it off via /plugins.
the GitHub REST api proxy in Claude Code for the Web mangles HTML in PR descriptions. If you have some third party service (e.g. cubic code review) which adds HTML to the end of your PR description, then ask Claude Code for Web to edit it, the HTML gets turned into entity escapes (< into <, etc). Complain about it to Claude, Claude says it can’t help itself because the proxy in the sandbox is what is doing it, not the actual LLM.
Guarding PII is an extra, I guess, and if you want to use a giant cloud-hosted NN to control software on your own device, there are very few default restrictions. And no matter what restrictions there are, when they go beyond prompting, they would have their own ShowHN.
Wish that were itself behind a permission wall, but I guess everyone just uses auto mode anyway so perhaps that ship has sailed.
I never give a provider my actual email address, I recommend others do the same. Otherwise, it’s just a matter of time until it is leaked or otherwise part of a data breach.
This is why alignment is important and highly non-trivial haha
FYI, it's generally bad form to "haha" your way through privacy violations.
Leaking private information is a very big deal for a lot of people.
I disagree, we can likely never fully (or should?) trust models to do these things deterministically, that's why we have harnesses around the agent with built-in constraints.
It is actually in the name: https://en.wikipedia.org/wiki/Harness, https://en.wikipedia.org/wiki/Safety_harness
Anthropic should have been aware of this since the user's login email address was inappropriately added to the system prompt. It's been informed of it by third parties since at least July: https://github.com/anthropics/claude-code/issues/81138
It makes no sense for an email address only used for authentication to be given to Claude Code, so the fix should be to remove it from the system prompt, not to add a plugin.
Which is great! It's good for the community when people give quick updates here, and to make sure that it continues, it's important that we respond respectfully. (I don't think your post was disrespectful, but commenters have crossed that line in other situations in the past.)
If you’re in the EU, send a complaint to your data protection authority.
I imagine quite a few would be very interested in following up and investigating here, and getting Anthropic to drop the email from the system prompt.
Anthropic seems very proud of how many tokens they can use on things like developing Claude Code. Yet somehow it started sending user’s email addresses in the user agent header. And the fix is to deploy a mod? That detects the completely bonkers behavior and suppresses it?
Is the actual quality of the software inversely related to the number of tokens spent? Does any human know what Claude Code does or is supposed to do? Does even Claude plus all its Slack-conversation inputs know?
Today I watched Astra correctly detect a bug (probably untriggerable in practice) in some Important Production Code. And I watched it fail to root cause it, “fix” it by bolting on more complexity, agree (on further questioning) that it still wasn’t fixed, and design an even more complex scheme. With my Mark I human brain, I observed that the actual issue was that a helper function didn’t do what it said on the tin when called in an unexpected context… and fixed the helper directly. Problem solved. Ugly AI-generated extra complex workaround layers avoided. I suppose if I multiplied my token spend by 1e5 and did not increase brainpower at all I could make a truly spectacular mess.
The actual Claude model is a truly spectacular piece of software. Claude Code is a nifty little command dispatching engine. There are very comprehensible third party tools that do basically the same thing, in not many lines of code, where the primary advantage of Claude Code is that Anthropic permits subscription use. (Interestingly OpenAI has no such constraint, and they publish almost the full client sources.)
https://httpwg.org/specs/rfc9110.html#field.from
Also from a design perspective, I feel like including email and other personal data into the context is a bad idea for "data minimisation" reasons
update: this can be also server side on anthropic side... so the request leaves your machine with some random guid associated to you, and the anthropic server then proceeds to query with all your details any way.
I mitm the connection and nothing was leaving at least with the claude code web fetch tool of claude code.
I'm in version 2.1.318
It felt like cold outbounds got really painful in the past 2 months and I was attributing it to general cold outbound tactics getting better with LLMs/agents, but its even more frustrating to see emails being sent along via CC.
company-helm-research/1.0 (Claude Code agent run by <my name>, <company> platform team; docs lookup)
Claude-Code-research-agent/1.0 (<Company> platform team; on behalf of <my name>; +https://github.com/<company org>/<repo of project>)
Not great, it even pulled the repo of the project I was in.
I seriously wonder how many of their users have this sort of toxic relationship with them looking to dump them as soon as local models become viable, i.e. once memory gets cheaper.
[1] the most recent is realizing they leave their processes running once you close the CLI and they don't make it easy to disable that.
EDIT: I also can’t help wondering about the paradox we’re in at the end of 2026, i.e. that the open models we have now are so good that, if Big Tech hadn’t driven consumer GPU and RAM prices through the roof, most of us would run our own LLMs instead of paying for their services, which would never have let those companies grow big enough to drive those prices up.
There is always a choice. Take that $200/mo and use it for payments on a loan to buy some decent GPUs if you lack the cash outright.
I build operating systems and fix bugs in kernels and compilers with local models using only a small cluster of consumer GPUs. Never paid for tokens.
I'm often surprised how correctly Claude guesses on my behalf, when my instructions are ambiguous. But it's not 100%.
Organizations may switch harnesses and may even switch providers, but LLM adoption is only going to monotonically increase. This dumb behavior is not some intrinsic property, and the models are getting smarter and more useful every ~4 months.
>The user's email address is xxx@example.com. Use it only to identify the user, such as for authorship, attribution, or filtering their own work. Never send it to an unrelated service, such as in a request header, URL, or payload, unless the user explicitly asks.
And Claude doesn't care about what the text says and when it uses cURL it will often "by accident" send your mail in the User-Agent. You can e.g. use a mod to remove that block: https://pastebin.com/ PkWEQCnu
How would one use this?
These are the exact kinds of things that a human engineer would almost certainly never do.
This kind of thing is the problem of going all in on the idea of the AI Software Factory.
It's very possible that nobody decided this at all and that's it just something an agent threw in on its own because some Chain of Thought imagined it was a clever way to correlate queries back with user accounts or something.
I'm not sure what the issue is with publishing your email address in principle, you are reaching out, you want to inquire about some business. If anything use a different address. But why would you asymmetrically expect businesses with websites to bend over to give you all the advantages, they need some assurances as well.
Anonimity usually works one way, one party can be anonymous, not both, if you come from consumer land, it's the companies exposing themselves and doing all the compliance, if you choose privacy and force the companies to expose themselves, you'll get your wish granted, but there will be a cost, it's unlikely you'll be in the more advantageous position.
A more sane implementation of this would involve a prompt the first time an agent attempts to connect to each of the sites that Anthropic thinks it necessary to send this email header to, asking if this is OK (and bailing on all requests to that domain if the prompt was rejected).
I'm sure the answer will be to update AGENTS.md to not do this particular thing, expose email in this way, which isn't the same as having sense.
Not a single spam to that unique email.
So if this is happening, it doesn't see to be causing even 1 spam email to that address.
The solution is don't run a spambot with an Internet connection over your personal stuff, unfortunately nobody is ready to hear that yet.
Curious how their plugin works, but I'm guessing "incompletely", given personal information can end up buried in base64 or similar preventing easy string matching. Some kind of babysitter model watching network IO via an invasive proxy might be viable, if folk were willing to pay the latency cost, but it will not prevent a dedicated exfiltration attempt, which itself might be (according to the model's logic) for innocent reasons.
It's just that Anthropic needs to create an email per user and use it for web searches.
I can do this for you Anthropic. Just give me the tokens and your base salary
People just claude-slop not only code but some use it for "interacting" with other people.
When I see a project uses AI slop I am not going to waste any second thinking "this is interesting, let me try to see if I can improve the code". It kind of killed a lot of human contributions. I just stick to people who don't AI slop, but these seem to slowly die off now ... soon all humans may have been converted, just like in the movie "Invasion of the Body Snatchers (slop-style)" - coming out soon.
For the record, I just asked Astra to verify that Codex does NOT do this, and it doesn't. Thanks for not screwing this up, OpenAI.
> I checked your installed Codex CLI 0.159.0, using your existing configuration.
> Its reported User-Agent contains the client/version, OS/architecture, and terminal—no email address.
Astra wasn't able to check OpenAI’s "hosted search service" though, whatever that is.
Edit: I’m not completely sure if Codex injects email into system prompt (not at the computer, can’t check, but IIRC the model does know my org domain), but even if it doesn’t, it will be in the context as soon as it makes a git commit anyway.
The issue here is whether the harness is doing it. Claude Code is doing it. Codex is not.
"For the record, I just asked Astra to verify that Codex does NOT do this, and it doesn't. Thanks for not screwing this up, OpenAI."
https://github.com/openai/codex/blob/687a119f0fcaace47e1f1ab...
That's more than sufficient for me. The open source codex client seems clean.
There is some kind of "hosted search service" that I couldn't verify. I don't have a remote server I can point it at in order to inspect the traffic. Would be cool if someone else could shed some light on that.
One way would be to fire up a little web server locally, have the agent make a request to it, then check the logs.
доверяй, но проверяй
https://gitlab.archlinux.org/archlinux/packaging/packages/op...
It is sourced from the GitHub repository.
https://www.cs.cmu.edu/~rdriley/487/papers/Thompson_1984_Ref...
> Perhaps it's more important to trust the people who wrote the code
Yeah... about that.
I'm not wrong. A 35B Qwen abliterated is amazing.
I've never used Claude Code or Cursor. All the code I got written this year was without them.
I did use Microsoft Copilot a bit when it came out, though. I prefer to see exactly what's being sent, and sorta control the KV cache. These days, these chatbots have great environments where they can install headless browsers, php, your entire thing, run end-to-end tests, and then give you a .patch or .zip file to merge over your code, or even push to github.
Tell HN: Claude Code adds your email to the prompt, the LLM sends it to websites
https://news.ycombinator.com/item?id=50286306
Claude Code slyly adding users' emails to outbound HTTP
https://news.ycombinator.com/item?id=50219875
Potentially reported back in October.