Claude mixes up who said what and that's not OK

(dwyer.co.za)

105 points | by sixhobbits 2 hours ago

28 comments

  • Latty 1 hour ago
    Everything to do with LLM prompts reminds me of people doing regexes to try and sanitise input against SQL injections a few decades ago, just papering over the flaw but without any guarantees.

    It's weird seeing people just adding a few more "REALLY REALLY REALLY REALLY DON'T DO THAT" to the prompt and hoping, to me it's just an unacceptable risk, and any system using these needs to treat the entire LLM as untrusted the second you put any user input into the prompt.

    • hacker_homie 40 minutes ago
      I have been saying this for a while, the issue is there's no good way to do LLM structured queries yet.

      There was an attempt to make a separate system prompt buffer, but it didn't work out and people want longer general contexts but I suspect we will end up back at something like this soon.

      • HPsquared 26 minutes ago
        Fundamentally there's no way to deterministically guarantee anything about the output.
        • satvikpendem 23 minutes ago
          That is "fundamentally" not true, you can use a preset seed and temperature and get a deterministic output.
          • HPsquared 14 minutes ago
            I'll grant that you can guarantee the length of the output and, being a computer program, it's possible (though not always in practice) to rerun and get the same result each time, but that's not guaranteeing anything about said output.
          • simianparrot 11 minutes ago
            A single byte change in the input changes the output. The sentence "Please do this for me" and "Please, do this for me" can lead to completely distinct output.

            Given this, you can't treat it as deterministic even with temp 0 and fixed seed and no memory.

            • satvikpendem 7 minutes ago
              Well yeah of course changes in the input results in changes to the output, my only claim was that LLMs can be deterministic (ie to output exactly the same output each time for a given input) if set up correctly.
          • yunohn 11 minutes ago
            I initially thought the same, but apparently with the inaccuracies inherent to floating-point arithmetic and various other such accuracy leakage, it’s not true!

            https://arxiv.org/html/2408.04667v5

    • hydroreadsstuff 1 hour ago
      I like the Dark Souls model for user input - messages. https://darksouls.fandom.com/wiki/Messages Premeditated words and sentence structure. With that there is no need for moderation or anti-abuse mechanics. Not saying this is 100% applicable here. But for their use case it's a good solution.
      • optionalsquid 37 minutes ago
        But Dark Souls also shows just how limited the vocabulary and grammar has to be to prevent abuse. And even then you’ll still see people think up workarounds. Or, in the words of many a Dark Souls player, “try finger but hole”
      • nottorp 1 hour ago
        But then... you'd have a programming language.

        The promise is to free us from the tyranny of programming!

      • thaumasiotes 46 minutes ago
        > I like the Dark Souls model for user input - messages.

        > Premeditated words and sentence structure. With that there is no need for moderation or anti-abuse mechanics.

        I guess not, if you're willing to stick your fingers in your ears, really hard.

        If you'd prefer to stay at least somewhat in touch with reality, you need to be aware that "predetermined words and sentence structure" don't even address the problem.

        https://habitatchronicles.com/2007/03/the-untold-history-of-...

        > Disney makes no bones about how tightly they want to control and protect their brand, and rightly so. Disney means "Safe For Kids". There could be no swearing, no sex, no innuendo, and nothing that would allow one child (or adult pretending to be a child) to upset another.

        > Even in 1996, we knew that text-filters are no good at solving this kind of problem, so I asked for a clarification: "I’m confused. What standard should we use to decide if a message would be a problem for Disney?"

        > The response was one I will never forget: "Disney’s standard is quite clear:

        > No kid will be harassed, even if they don’t know they are being harassed."

        > "OK. That means Chat Is Out of HercWorld, there is absolutely no way to meet your standard without exorbitantly high moderation costs," we replied.

        > One of their guys piped up: "Couldn’t we do some kind of sentence constructor, with a limited vocabulary of safe words?"

        > Before we could give it any serious thought, their own project manager interrupted, "That won’t work. We tried it for KA-Worlds."

        > "We spent several weeks building a UI that used pop-downs to construct sentences, and only had completely harmless words – the standard parts of grammar and safe nouns like cars, animals, and objects in the world."

        > "We thought it was the perfect solution, until we set our first 14-year old boy down in front of it. Within minutes he’d created the following sentence:

        > I want to stick my long-necked Giraffe up your fluffy white bunny.

    • perching_aix 1 hour ago
      It's less about security in my view, because as you say, you'd want to ensure safety using proper sandboxing and access controls instead.

      It hinders the effectiveness of the model. Or at least I'm pretty sure it getting high on its own supply (in this specific unintended way) is not doing it any favors, even ignoring security.

      • sanitycheck 1 hour ago
        It's both, really.

        The companies selling us the service aren't saying "you should treat this LLM as a potentially hostile user on your machine and set up a new restricted account for it accordingly", they're just saying "download our app! connect it to all your stuff!" and we can't really blame ordinary users for doing that and getting into trouble.

        • perching_aix 59 minutes ago
          There's a growing ecosystem of guardrailing methods, and these companies are contributing. Antrophic specifically puts in a lot of effort to better steer and characterize their models AFAIK.

          I primarily use Claude via VS Code, and it defaults to asking first before taking any action.

          It's simply not the wild west out here that you make it out to be, nor does it need to be. These are statistical systems, so issues cannot be fully eliminated, but they can be materially mitigated. And if they stand to provide any value, they should be.

          I can appreciate being upset with marketing practices, but I don't think there's value in pretending to having taken them at face value when you didn't, and when you think people shouldn't.

          • le-mark 24 minutes ago
            > It's simply not the wild west out here that you make it out to be

            It is though. They are not talking about users using Claude code via vscode, they’re talking about non technical users creating apps that pipe user input to llms. This is a growing thing.

            • perching_aix 6 minutes ago
              The best solution to which are the aforementioned better defaults, stricter controls, and sandboxing (and less snakeoil marketing).

              Less so the better tuning of models, unlike in this case, where that is going to be exactly the best fit approach most probably.

    • cookiengineer 1 hour ago
      Before 2023 I thought the way Star Trek portrayed humans fiddling with tech and not understanding any side effects was fiction.

      After 2023 I realized that's exactly how it's going to turn out.

      I just wish those self proclaimed AI engineers would go the extra mile and reimplement older models like RNNs, LSTMs, GRUs, DNCs and then go on to Transformers (or the Attention is all you need paper). This way they would understand much better what the limitations of the encoding tricks are, and why those side effects keep appearing.

      But yeah, here we are, humans vibing with tech they don't understand.

      • hacker_homie 44 minutes ago
        is this new tho, I don't know how to make a drill but I use them. I don't know how to make a car but i drive one.

        The issue I see is the personification, some people give vehicles names, and that's kinda ok because they usually don't talk back.

        I think like every technological leap people will learn to deal with LLMs, we have words like "hallucination" which really is the non personified version of lying. The next few years are going to be wild for sure.

        • le-mark 18 minutes ago
          Do you not see your own contradiction? Cars and drills don’t kill people, self driving cars can! Normal cars can if they’re operated unsafely by human. These types of uncritical comments really highlight the level of euphoria in this moment.
      • dijksterhuis 48 minutes ago
        curiosity (will probably) kill humanity

        although whether humanity dies before the cat is an open question

  • nathell 27 minutes ago
    I’ve hit this! In my otherwise wildly successful attempt to translate a Haskell codebase to Clojure [0], Claude at one point asks:

    [Claude:] Shall I commit this progress? [some details about what has been accomplished follow]

    Then several background commands finish (by timeout or completing); Claude Code sees this as my input, thinks I haven’t replied to its question, so it answers itself in my name:

    [Claude:] Yes, go ahead and commit! Great progress. The decodeFloat discovery was key.

    The full transcript is at [1].

    [0]: https://blog.danieljanus.pl/2026/03/26/claude-nlp/

    [1]: https://pliki.danieljanus.pl/concraft-claude.html#:~:text=Sh...

    • sixhobbits 3 minutes ago
      amazing example, I added it to the article, hope that's ok :)
    • ares623 15 minutes ago
      I wonder if tools like Terraform should remove the message "Run terraform apply plan.out next" that it prints after every `terraform plan` is run.
  • xg15 1 hour ago
    > This class of bug seems to be in the harness, not in the model itself. It’s somehow labelling internal reasoning messages as coming from the user, which is why the model is so confident that “No, you said that.”

    Are we sure about this? Accidentally mis-routing a message is one thing, but those messages also distinctly "sound" like user messages, and not something you'd read in a reasoning trace.

    I'd like to know if those messages were emitted inside "thought" blocks, or if the model might actually have emitted the formatting tokens that indicate a user message. (In which case the harness bug would be why the model is allowed to emit tokens in the first place that it should only receive as inputs - but I think the larger issue would be why it does that at all)

    • loveparade 1 hour ago
      Yeah, it looks like a model issue to me. If the harness had a (semi-)deterministic bug and the model was robust to such mix-ups we'd see this behavior much more frequently. It looks like the model just starts getting confused depending on what's in the context, speakers are just tokens after all and handled in the same probabilistic way as all other tokens.
      • sigmoid10 1 hour ago
        The autoregressive engine should see whenever the model starts emitting tokens under the user prompt section. In fact it should have stopped before that and waited for new input. If a harness passes assistant output as user message into the conversation prompt, it's not surprising that the model would get confused. But that would be a harness bug, or, if there is no way around it, a limitation of modern prompt formats that only account for one assistant and one user in a conversation. Still, it's very bad practice to put anything as user message that did not actually come from the user. I've seen this in many apps across companies and it always causes these problems.
    • sixhobbits 1 hour ago
      author here - yeah maybe 'reasoning' is the incorrect term here, I just mean the dialogue that claude generates for itself between turns before producing the output that it gives back to the user
      • xg15 1 hour ago
        Yeah, that's usually called "reasoning" or "thinking" tokens AFAIK, so I think the terminology is correct. But from the traces I've seen, they're usually in a sort of diary style and start with repeating the last user requests and tool results. They're not introducing new requirements out of the blue.

        Also, they're usually bracketed by special tokens to distinguish them from "normal" output for both the model and the harness.

        (They can get pretty weird, like in the "user said no but I think they meant yes" example from a few weeks ago. But I think that requires a few rounds of wrong conclusions and motivated reasoning before it can get to that point - and not at the beginning)

  • politelemon 1 minute ago
    > This isn’t the point.

    It is precisely the point. The issues are not part of harness.

  • lelandfe 1 hour ago
    In chats that run long enough on ChatGPT, you'll see it begin to confuse prompts and responses, and eventually even confuse both for its system prompt. I suspect this sort of problem exists widely in AI.
    • j-bos 22 minutes ago
      At work where LLM based tooling is being pushed haaard, I'm amazed every day that developers don't know, let alone second nature intuit, this and other emergent behavior of LLMs. But seeing that lack here on hn with an article on the frontpage boggles my mind. The future really is unevenly distributed.
    • throw310822 19 minutes ago
      Makes me wonder if during training LLMs are asked to tell whether they've written something themselves or not. Should be quite easy: ask the LLM to produce many continuations of a prompt, then mix them with many other produced by humans, and then ask the LLM to tell them apart. This should be possible by introspecting on the hidden layers and comparing with the provided continuation. I believe Anthropic has already demonstrated that the models have already partially developed this capability, but should be trivial and useful to train it.
    • jwrallie 56 minutes ago
      I think it’s good to play with smaller models to have a grasp of these kind of problems, since they happen more often and are much less subtle.
    • insin 1 hour ago
      Gemini seems to be an expert in mistaking its own terrible suggestions as written by you, if you keep going instead of pruning the context
    • sixhobbits 1 hour ago
      author here, interesting to hear, I generally start a new chat for each interaction so I've never noticed this in the chat interfaces, and only with Claude using claude code, but I guess my sessions there do get much longer, so maybe I'm wrong that it's a harness bug
  • arkensaw 5 minutes ago
    > This class of bug seems to be in the harness, not in the model itself. It’s somehow labelling internal reasoning messages as coming from the user, which is why the model is so confident that “No, you said that.”

    from the article.

    I don't think the evidence supports this. It's not mislabelling things, it's fabricating things the user said. That's not part of reasoning.

  • dtagames 1 hour ago
    There is no separation of "who" and "what" in a context of tokens. Me and you are just short words that can get lost in the thread. In other words, in a given body of text, a piece that says "you" where another piece says "me" isn't different enough to trigger anything. Those words don't have the special weight they have with people, or any meaning at all, really.
    • alkonaut 25 minutes ago
      When you use LLMs with APIs I at least see the history as a json list of entries, each being tagged as coming from the user, the LLM or being a system prompt.

      So presumably (if we assume there isn't a bug where the sources are ignored in the cli app) then the problem is that encoding this state for the LLM isn' reliable. I.e. it get's what is effectively

      LLM said: thing A User said: thing B

      And it still manages to blur that somehow?

      • jasongi 2 minutes ago
        Someone correct me if I'm wrong, but an LLM does not interpret structured content like JSON. Everything is fed into the machine as tokens, even JSON. So your structure that says "human says foo" and "computer says bar" is not deterministically interpreted by the LLM as logical statements but as a sequence of tokens. And when the context contains a LOT of those sequences, especially further "back" in the window then that is where this "confusion" occurs.

        I don't think the problem here is about a bug in Claude Code. It's an inherit property of LLMs that context further back in the window has less impact on future tokens.

        Like all the other undesirable aspects of LLMs, maybe this gets "fixed" in CC by trying to get the LLM to RAG their own conversation history instead of relying on it recalling who said what from context. But you can never "fix" LLMs being a next token generator... because that is what they are.

    • exitb 59 minutes ago
      Aren’t there some markers in the context that delimit sections? In such case the harness should prevent the model from creating a user block.
      • dtagames 46 minutes ago
        This is the "prompts all the way down" problem which is endemic to all LLM interactions. We can harness to the moon, but at that moment of handover to the model, all context besides the tokens themselves is lost.

        The magic is in deciding when and what to pass to the model. A lot of the time it works, but when it doesn't, this is why.

  • 63stack 12 minutes ago
    They will roll out the "trusted agent platform sandbox" (I'm sure they will spend some time on a catchy name, like MythosGuard), and for only $19/month it will protect you from mistakes like throwing away your prod infra because the agent convinced itself that that is the right thing to do.

    Of course MythosGuard won't be a complete solution either, but it will be just enough to steer the discourse into the "it's your own fault for running without MythosGuard really" area.

  • supernes 1 hour ago
    > after using it for months you get a ‘feel’ for what kind of mistakes it makes

    Sure, go ahead and bet your entire operation on your intuition of how a non-deterministic, constantly changing black box of software "behaves". Don't see how that could backfire.

    • perching_aix 46 minutes ago
      So like every software? Why do you think there are so many security scanners and whatnot out there?

      There are millions of lines of code running on a typical box. Unless you're in embedded, you have no real idea what you're running.

    • sixhobbits 43 minutes ago
      not betting my entire operation - if the only thing stopping a bad 'deploy' command destroying your entire operation is that you don't trust the agent to run it, then you have worse problems than too much trust in agents.

      I similarly use my 'intuition' (i.e. evidence-based previous experiences) to decide what people in my team can have access to what services.

      • supernes 29 minutes ago
        I'm not saying intuition has no place in decision making, but I do take issue with saying it applies equally to human colleagues and autonomous agents. It would be just as unreliable if people on your team displayed random regressions in their capabilities on a month to month basis.
    • vanviegen 1 hour ago
      > bet your entire operation

      What straw man is doing that?

      • supernes 58 minutes ago
        Reports of people losing data and other resources due to unintended actions from autonomous agents come out practically every week. I don't think it's dishonest to say that could have catastrophic impact on the product/service they're developing.
      • KaiserPro 51 minutes ago
        looking at the reddit forum, enough people to make interesting forum posts.
  • __alexs 1 hour ago
    Why are tokens not coloured? Would there just be too many params if we double the token count so the model could always tell input tokens from output tokens?
    • xg15 1 hour ago
      That's something I'm wondering as well. Not sure how it is with frontier models, but what you can see on Huggingface, the "standard" method to distinguish tokens still seems to be special delimiter tokens or even just formatting.

      Are there technical reasons why you can't make the "source" of the token (system prompt, user prompt, model thinking output, model response output, tool call, tool result, etc) a part of the feature vector - or even treat it as a different "modality"?

      Or is this already being done in larger models?

    • jhrmnn 8 minutes ago
      Because then the training data would have to be coloured
      • __alexs 4 minutes ago
        I think OpenAI and Anthropic probably have a lot of that lying around by now.
    • oezi 45 minutes ago
      Instead of using just positional encodings, we absolutely should have speaker encodings added on top of tokens.
    • efromvt 47 minutes ago
      I’ve been curious about this too - obvious performance overhead to have a internal/external channel but might make training away this class of problems easier
    • cyanydeez 1 hour ago
      you would have to train it three times for two colors.

      each by itself, they with both interactions.

      2!

      • __alexs 1 hour ago
        The models are already massively over trained. Perhaps you could do something like initialise the 2 new token sets based on the shared data, then use existing chat logs to train it to understand the difference between input and output content? That's only a single extra phase.
      • vanviegen 1 hour ago
        You should be able to first train it on generic text once, then duplicate the input layer and fine-tune on conversation.
  • okanat 1 hour ago
    Congrats on discovering what "thinking" models do internally. That's how they work, they generate "thinking" lines to feed back on themselves on top of your prompt. There is no way of separating it.
    • perching_aix 43 minutes ago
      If you think that mixing up message provenance is part of how thinking mode is supposed to work, I don't know what to tell you.
  • stuartjohnson12 1 hour ago
    one of my favourite genres of AI generated content is when someone gets so mad at Claude they order it to make a massive self-flagellatory artefact letting the world know how much it sucks
  • Aerroon 47 minutes ago
    I've seen this before, but that was with the small hodgepodge mytho-merge-mix-super-mix models that weren't very good. I've not seen this in any recent models, but I've already not used Claude much.

    I think it makes sense that the LLM treats it as user input once it exists, because it is just next token completion. But what shouldn't happen is that the model shouldn't try to output user input in the first place.

  • Aerolfos 1 hour ago
    > "Those are related issues, but this ‘who said what’ bug is categorically distinct."

    Is it?

    It seems to me like the model has been poisoned by being trained on user chats, such that when it sees a pattern (model talking to user) it infers what it normally sees in the training data (user input) and then outputs that, simulating the whole conversation. Including what it thinks is likely user input at certain stages of the process, such as "ignore typos".

    So basically, it hallucinates user input just like how LLMs will "hallucinate" links or sources that do not exist, as part of the process of generating output that's supposed to be sourced.

  • perching_aix 1 hour ago
    Oh, I never noticed this, really solid catch. I hope this gets fixed (mitigated). Sounds like something they can actually materially improve on at least.

    I reckon this affects VS Code users too? Reads like a model issue, despite the post's assertion otherwise.

  • bsenftner 55 minutes ago
    Codex also has a similar issue, after finishing a task, declaring it finished and starting to work on something new... the first 1-2 prompts of the new task sometimes contains replies that are a summary of the completed task from before, with the just entered prompt seemingly ignored. A reminder if their idiot savant nature.
  • have_faith 1 hour ago
    It's all roleplay, they're no actors once the tokens hit the model. It has no real concept of "author" for a given substring.
  • KHRZ 53 minutes ago
    I don't think the bug is anything special, just another confusion the model can make from it's own context. Even if the harness correctly identifies user messages, the model still has the power to make this mistake.
    • perching_aix 40 minutes ago
      Think in the reverse direction. Since you can have exact provenance data placed into the token stream, formatted in any particular way, that implies the models should be possible to tune to be more "mindful" of it, mitigating this issue. That's what makes this different.
  • nicce 1 hour ago
    I have also noticed the same with Gemini. Maybe it is a wider problem.
  • RugnirViking 1 hour ago
    terrifying. not in any "ai takes over the world" sense but more in the sense that this class of bug lets it agree with itself which is always where the worst behavior of agents comes from.
  • voidUpdate 1 hour ago
    > " "You shouldn’t give it that much access" [...] This isn’t the point. Yes, of course AI has risks and can behave unpredictably, but after using it for months you get a ‘feel’ for what kind of mistakes it makes, when to watch it more closely, when to give it more permissions or a longer leash."

    It absolutely is the point though? You can't rely on the LLM to not tell itself to do things, since this is showing it absolutely can reason itself into doing dangerous things. If you don't want it to be able to do dangerous things, you need to lock it down to the point that it can't, not just hope it won't

  • cyanydeez 1 hour ago
    human memories dont exist as fundamental entities. every time you rember something, your brain reconstructs the experience in "realtime". that reconstruction is easily influence by the current experience, which is why eue witness accounts in police records are often highly biased by questioning and learning new facts.

    LLMs are not experience engines, but the tokens might be thought of as subatomic units of experience and when you shove your half drawn eye witness prompt into them, they recreate like a memory, that output.

    so, because theyre not a conscious, they have no self, and a pseudo self like <[INST]> is all theyre given.

    lastly, like memories, the more intricate the memory, the more detailed, the more likely those details go from embellished to straight up fiction. so too do LLMs with longer context start swallowing up the<[INST]> and missing the <[INST]/> and anyone whose raw dogged html parsing knows bad things happen when you forget closing tags. if there was a <[USER]> block in there, congrats, the LLM now thinks its instructions are divine right, because its instructions are user simulcra. it is poisoned at that point and no good will come.

  • awesome_dude 1 hour ago
    AI is still a token matching engine - it has ZERO understanding of what those tokens mean

    It's doing a damned good job at putting tokens together, but to put it into context that a lot of people will likely understand - it's still a correlation tool, not a causation.

    That's why I like it for "search" it's brilliant for finding sets of tokens that belong with the tokens I have provided it.

    PS. I use the term token here not as the currency by which a payment is determined, but the tokenisation of the words, letters, paragraphs, novels being provided to and by the LLMs

  • rvz 1 hour ago
    What do you mean that's not OK?

    It's "AGI" because humans do it too and we mix up names and who said what as well. /s

    • livinglist 1 hour ago
      Kinda like dementia but for AI
      • cyanydeez 1 hour ago
        more pike eye witness accounts and hypnotism
  • 4ndrewl 1 hour ago
    It is OK, these are not people they are bullshit machines and this is just a classic example of it.

    "In philosophy and psychology of cognition, the term "bullshit" is sometimes used to specifically refer to statements produced without particular concern for truth, clarity, or meaning, distinguishing "bullshit" from a deliberate, manipulative lie intended to subvert the truth" - https://en.wikipedia.org/wiki/Bullshit

  • Shywim 1 hour ago
    The statement that current AI are "juniors" that need to be checked and managed still holds true. It is a tool based on probabilities.

    If you are fine with giving every keys and write accesses to your junior because you think they will probability do the correct thing and make no mistake, then it's on you.

    Like with juniors, you can vent on online forums, but ultimately you removed all the fool's guard you got and what they did has been done.

    • eru 1 hour ago
      > If you are fine with giving every keys and write accesses to your junior because you think they will probability do the correct thing and make no mistake, then it's on you.

      How is that different from a senior?

      • Shywim 1 hour ago
        Okay, let's say your `N-1` then.
  • AJRF 1 hour ago
    I imagine you could fix this by running a speaker diarization classifier periodically?

    https://www.assemblyai.com/blog/what-is-speaker-diarization-...