Kei Nishimura-Gasparian

• Kei Nishimura-Gasparian 26 Oct 2025 14:01 UTC

  5 points

  0

  in reply to: Nathan Helm-Burger’s comment on: Towards a Ty­pol­ogy of Strange LLM Chains-of-Thought

  Anthropic says in their system card that Claude Sonnet 3.7 showed raw CoTs, and that Claude Opus 4 and Sonnet 4 show raw CoTs unless the CoT is especially long, in which case it is summarized. They also say this summarization happens about 5% of the time. According to the 4.5 system card, Claude Sonnet 4.5 reasoning text works the same way, but instead of giving a number, they say summarization happens in ‘a very small minority of cases’.

  I agree that Anthropic and GDM may be reinforcing legibility in some way given how much more structured their CoTs look.

  Claude 4 system card: https://​​www-cdn.anthropic.com/​​6d8a8055020700718b0c49369f60816ba2a7c285.pdf#page=8

  Claude Sonnet 4.5 system card: https://​​assets.anthropic.com/​​m/​​12f214efcc2f457a/​​original/​​Claude-Sonnet-4-5-System-Card.pdf#page=9

Can you find the stegano­graph­i­cally hid­den mes­sage?

• Kei Nishimura-Gasparian 14 Oct 2025 19:27 UTC

  3 points

  0

  on: Re­con­tex­tu­al­iza­tion Miti­gates Speci­fi­ca­tion Gam­ing Without Mod­ify­ing the Specification

  In the context of specification gaming, modifying instructions in hindsight based on observed behavior could provide recontextualization-like effects.

  Maybe this could be one way to train against a monitor without the bad side effects? If your reward hack monitor flags reward hacking you would add a hack instruction to the prompt. You can also do this for any other bad behavior you can catch with a monitor like deception or sycophancy or uninterpretable CoT.

  If you only change the prompts corresponding to the completions flagged by monitors and nothing else, this might capture most of the benefit and have the upside of making your model updates less off-policy and have less of an impact on instruction following. On the other hand, you might miss some kinds of bad behavior and inadvertently reinforce them.

• Kei Nishimura-Gasparian 5 Oct 2025 16:46 UTC

  1 point

  0

  on: Rea­sons to sell fron­tier lab equity to donate now rather than later

  About a year ago, Horizon had a policy of not accepting donations from any individuals employed in the AI industry. Is this no longer the case?

• Kei Nishimura-Gasparian 9 Sep 2025 21:49 UTC

  8 points

  2

  on: GPT-oss is an ex­tremely stupid model

  Interestingly, in the original agentic misalignment paper, o3 and o4-mini were unique in that they also frequently got confused and played as another character (see Appendix 9). There may be something specific in how OpenAI trained those two models and gpt-oss that caused this confusion.

  The agentic misalignment researchers got o3 and o4-mini to better understand the scenario by making a few changes to the setup (described in Appendix 9.1). Maybe those same changes could get gpt-oss to understand the scenario as well.

• Kei Nishimura-Gasparian 30 Aug 2025 13:48 UTC

  1 point

  0

  on: Will Any Crap Cause Emer­gent Misal­ign­ment?

  Am I correctly understanding that the effect size shown in the graph is very small? It seems like the mean harmfulness score is not much higher for any of the evals, even if the effect size is technically statistically significant.

• Kei Nishimura-Gasparian 28 Aug 2025 21:49 UTC

  15 points

  6

  in reply to: nielsrolf’s comment on: Will Any Crap Cause Emer­gent Misal­ign­ment?

  Maybe not any distributional shift, but it does seem noteworthy that of the examples discussed, the answers that seem to me to be more OOD for the model (unpopular preferences, the examples given in this post, and potentially insecure code) produce emergent misalignment, while the answers that seem more in distribution (secure code, educational insecure code, popular preferences) don’t produce emergent misalignment.^[1]

  As a hypothesis, maybe the model has partially entangled representations for ‘normal’ behavior and ‘aligned’ behavior, and so pushing the model towards abnormal behavior induces at least some emergent misalignment. Though I’d be surprised if this were the primary mechanism behind the EM observed when training on explicitly misaligned data like insecure code.

  ---

  1. ↩︎

     To a first approximation, we should be able to measure how OOD some completion is by using per-token loss of the pre-fine tuned model on that data.

• Kei Nishimura-Gasparian 17 Aug 2025 23:02 UTC

  1 point

  0

  on: Train­ing a Re­ward Hacker De­spite Perfect Labels

  Interesting work! I’ve been hypothesizing that behavioral change from RL on perfect reward signals is a potential mechanism for increased inference-time hacking in reasoning models (alongside generalizing from reward hacking experienced during training), so it’s great to see evidence that this can happen in practice. Some thoughts:

  But we do think it’s surprising that this effect can overpower the effect of the training responses resulting in an honest final answer 100% of the time.

  My guess is that the model has a much weaker prior on the types of reasoning you are reinforcing compared to the types of final answers you are reinforcing. So the main effect of this training is to make the model’s reasoning more ‘hacky’, which due to the model’s priors on making its final answers consistent with its reasoning, makes the model reward hack more. This hypothesis is at least somewhat supported by the fact that your re-contextualized training reduces the hack rate of models that already hack a lot.

  This raises the concern that, if some training procedure causes the model to reason more about reward hacking, it might generalize to increased hacking. That generalization might happen regardless of how well the reward model can detect hacks!

  This is probably true, and I suspect we can be more concrete. Not only does training on thinking about reward hacking increase the rate of reward hacking, it may also be true that there is a wide array of reasoning traits that models can learn through training that make reward hacky reasoning more likely, at least in certain settings. Potential examples of this are thinking about how you are evaluated, doing situationally aware reasoning, learning creative problem solving, caring about scoring highly, or even learning to backtrack when your current approach is not working.
  
  If possible, I’d be excited to see a more detailed investigation of how the types of reasoning the model does changes as a function of training time, and how that corresponds to rate of reward hacking.

• Kei Nishimura-Gasparian 5 Aug 2025 23:12 UTC

  13 points

  2

  on: Steer­ing Out-of-Distri­bu­tion Gen­er­al­iza­tion with Con­cept Abla­tion Fine-Tuning

  I’m curious if you have an opinion on the relation between this work and the fine-tuning experiments in the recent Persona vector paper.

  In this work, you find vectors for concepts that you don’t want the model to use and ablate them during training to stop the model from learning to use those concepts. In the Persona vector work, the authors find vectors for concepts they don’t want the model to use, and then add them during training so the model doesn’t need to learn to use those concepts. Interestingly, doing apparently opposite things results in similar outcomes.

  Do you think there are any connections between the mechanisms through which these two methods work? Do you have opinions on the situations where one technique may be better or worse than the other?

• Kei Nishimura-Gasparian 12 Jul 2025 23:59 UTC

  2 points

  0

  in reply to: Raphael Roche’s comment on: Early Signs of Stegano­graphic Ca­pa­bil­ities in Fron­tier LLMs

  I agree that a well-designed paraphraser would make nearly all of the hard-to-detect steganography we saw in our experiments go away. It also just makes the task much harder for the model. My guess would be that the first time some company creates a model that is able to do consistent steganography under standard affordances, it won’t be able to do consistent steganography with a well-designed paraphraser. So if we are building a safety case, we can first rely on model inability to do steganography. Once it becomes the case that models are capable of steganography, we can put in place a paraphraser mitigation and then rely on model inability to do steganography that bypasses a paraphraser. Eventually that too will fail and we’ll need to rely on something else.

  As StanislavKrym mentions, models eventually may use steganography techniques that paraphrasing does not remove. This seems especially plausible in situations like untrusted monitoring/​control where the model is trying to pass a single outcome signal like a password indicating a backdoor was model-generated. Still though, I suspect it will take some time for models to learn how to do this consistently, at which point we can try other mitigations. Paraphrasing also has the benefit of making any steganography that remains after paraphrasing far less information dense than it would be otherwise.

Early Signs of Stegano­graphic Ca­pa­bil­ities in Fron­tier LLMs

• Kei Nishimura-Gasparian 30 Apr 2025 23:51 UTC

  6 points

  1

  in reply to: Steven Byrnes’s comment on: steve2152′s Shortform

  On a second review it seems to me the links are consistent with both definitions. Interestingly the google sheet linked in the blog post, which I think is the most canonical collection of examples of specification gaming, contains examples of evaluation-time hacking, like METR finding that o1-preview would sometimes pretend to fine-tune a model to pass an evaluation. Though that’s not definitive, and of course the use of the term can change over time.

  I agree that most historical discussion of this among people as well as in the GDM blog post focuses on RL optimization and situations where a model is literally getting a high RL reward. I think this is partly just contingent on these kinds of behaviors historically tending to emerge in an RL setting and not generalizing very much between different environments. And I also think the properties of reward hacks we’re seeing now are very different from the properties we saw historically, and so the implications of the term reward hack now are often different from the implications of the term historically. Maybe this suggests expanding the usage of the term to account for the new implications, or maybe it suggests just inventing a new term wholesale.

  I suppose the way I see it is that for a lot of tasks, there is something we want the model to do (which I’ll call the goal), and a literal way we evaluate the model’s behavior (which I’ll call the proxy, though we can also use the term specification). In most historical RL training, the goal was not given to the model, it lay in the researcher’s head, and the proxy was the reward signal that the model was trained on. When working with LLMs nowadays, whether it be during RL training or test-time evaluation or when we’re just prompting a model, we try to write down a good description of the goal in our prompt. What the proxy is depends on the setting. In an RL setting it’s the reward signal, and in an explicit evaluation it’s the evaluation function. When prompting, we sometimes explicitly write a description of the proxy in the prompt. In many circumstances it’s undefined, though perhaps the best analogue of the proxy in the general prompt setting is just whether the human thinks the model did what they wanted the model to do.

  So now to talk about some examples:

  • If I give a model a suite of coding tasks, and I evaluate the tasks by checking if running the test file works or not (as in the METR eval), then I would call it specification gaming, and the objective the model is scoring highly by is the results of the evaluation. By objective I am referring to the actual score the model gets on the evaluation, not what the human wants.

  • In just pure prompt settings where there is no eval going on, I’m more hesitant to use the terms reward hacking or specification gaming because the proxy is unclear. I do sometimes use the term to refer to the type of behavior that would’ve received a high proxy score if I had been running an eval, though this is a bit sloppy

    • I think a case could be made for saying a model is specification gaming if it regularly produces results that appear to fulfill prompts given to them by users, according to those users, while secretly doing something else, even if no explicit evaluation is going on. (So using the terminology mentioned before, it succeeds as per the proxy “the human thinks the model did what they wanted the model to do” even if it didn’t fulfill the goal given to it in the prompt.) But I do think this is more borderline and I don’t tend to use the term very much in this situation. And if models just lie or edit tests without fooling the user, they definitely aren’t specification gaming even by this definition.

      • Maybe a term like deceptive instruction following would be better to use here? Although that term also has the problem of ascribing intentionality.

    • Perhaps you can say that the implicit proxy in many codebases is successfully passing the tests, though that also seems borderline

  An intuition pump for why I like to think about things this way. Let’s imagine I build some agentic environment for my friend to use in RL training. I have some goal behavior I want the model to display, and I have some proxy reward signal I’ve created to evaluate the model’s trajectories in this environment. Let’s now say my friend puts the model in the environment and it performs a set of behaviors that get evaluated highly but are undesired according to my goal. It seems weird to me that I won’t know whether or not this counts as specification gaming until I’m told whether or not that reward signal was used to train the model. I think I should just be able to call this behavior specification gaming independent of this. Taking a step further, I also want to be able to call it specification gaming even if I never intended for the evaluation score to be used to train the model.

  On an end note, this conversation as well as Rauno Arike’s comment is making me want to use the term specification gaming more often in the future for describing either RL-time or inference-time evaluation hacking and reward hacking more for RL-time hacking. And maybe I’ll also be more likely to use terms like loophole-finding or deceptive instruction following or something else, though these terms have limitations as well, and I’ll need to think more about what makes sense.

• Kei Nishimura-Gasparian 29 Apr 2025 22:16 UTC

  LW: 5 AF: 4

  0

  AF

  in reply to: Steven Byrnes’s comment on: steve2152′s Shortform

  It’s pretty common for people to use the terms “reward hacking” and “specification gaming” to refer to undesired behaviors that score highly as per an evaluation or a specification of an objective, regardless of whether that evaluation/​specification occurs during RL training. I think this is especially common when there is some plausible argument that the evaluation is the type of evaluation that could appear during RL training, even if it doesn’t actually appear there in practice. Some examples of this:

  • OpenAI described o1-preview succeeding at a CTF task in an undesired way as reward hacking.

  • Anthropic described Claude 3.7 Sonnet giving an incorrect answer aligned with a validation function in a CoT faithfulness eval as reward hacking. They also used the term when describing the rates of models taking certain misaligned specification-matching behaviors during an evaluation after being fine-tuned on docs describing that Claude does or does not like to reward hack.

  • This relatively early DeepMind post on specification gaming and the blog post from Victoria Krakovna that it came from (which might be the earliest use of the term specification gaming?) also gives a definition consistent with this.

  I think the literal definitions of the words in “specification gaming” align with this definition (although interestingly not the words in “reward hacking”). The specification can be operationalized as a reward function in RL training, as an evaluation function or even via a prompt.

  I also think it’s useful to have a term that describes this kind of behavior independent of whether or not it occurs in an RL setting. Maybe this should be reward hacking and specification gaming. Perhaps as Rauno Arike suggests it is best for this term to be specification gaming, and for reward hacking to exclusively refer to this behavior when it occurs during RL training. Or maybe due to the confusion it should be a whole new term entirely. (I’m not sure that the term “ruthless consequentialism” is the ideal term to describe this behavior either as it ascribes certain intentionality that doesn’t necessarily exist.)

• Kei Nishimura-Gasparian 25 Apr 2025 16:34 UTC

  1 point

  0

  in reply to: Bronson Schoen’s comment on: Re­ward hack­ing is be­com­ing more so­phis­ti­cated and de­liber­ate in fron­tier LLMs

  Thanks for making the distinction! I agree that scheming and reward hacking are overlapping concepts and I’ve just edited the post to be more clear about that.

  I think your model of how scheming and reward hacking are likely to coincide in the future makes a lot of sense. It also seems possible that sufficiently strong monitoring and oversight systems (in certain domains) will make it impossible for models to reward hack without scheming.

Re­ward hack­ing is be­com­ing more so­phis­ti­cated and de­liber­ate in fron­tier LLMs

• Kei Nishimura-Gasparian 27 Mar 2025 4:20 UTC

  1 point

  0

  in reply to: Fabien Roger’s comment on: Fa­bien’s Shortform

  Do you think this means that if Claude 3.7 Sonnet does in fact use steganography then your earlier experiment wouldn’t have found evidence for it, since you didn’t fine-tune for long enough for the model to learn the scheme?

  Of course this experiment also suggests one should lower their likelihood of Claude 3.7 Sonnet using steganography at all.

Au­dit­ing lan­guage mod­els for hid­den objectives

• Kei Nishimura-Gasparian 26 Feb 2025 23:13 UTC

  10 points

  0

  on: Kei’s Shortform

  For two hours yesterday, I watched the twitch channel ClaudePlaysPokemon, which shows a Claude 3.7 Sonnet agent playing through the game Pokémon Red. Below I list some limitations I observed with the Claude agent. I think many of these limitations will carry over to agents built on other current frontier models and on other agentic tasks.

  • Claude has poor visual understanding. For example, Claude would often think it was next to a character when it was clearly far away from it. It would also often misidentify objects in its field of vision

  • The Claude agent is extremely slow. It tends to need to think for hundreds of tokens just to move one or two spaces or press A a single time. For example, it can sometimes take over a minute for the model to walk into a Pokemon center from the entrance and heal its Pokemon. Speed will become less of a problem as inference times continue to increase, but I suspect it will still be necessary for future agents to distill common actions to not require thinking and to allow the model to reason over higher-level actions instead of each individual one

  • The 200K token context window is a significant bottleneck. This was surprising to me since I had thought a context window that can store a medium-length book should be able to hold a large enough chunk of a game in memory to not be a significant problem. But when the model is outputting ~200 tokens per each action which is often a single button press, and when it regularly processes screenshots of the game which require an unknown but likely large number of tokens, the context window can fill up quite fast. At one point I measured it to take ~7.5 minutes to fill up the context window, which due to the model’s slowness was only enough to leave a Pokemon center, fight a few Pokemon, and then go back to the center.

  • Even though Claude makes a lot of mistakes within a context window, its biggest mistakes occur when it needs to accomplish tasks that span multiple context windows. Because the context window is too small, the model often forgets things it did very recently and gets stuck into loops. This makes it very bad at tasks that require systematic exploration. In one particularly infuriating sequence, Claude entered a house, talked to its residents, left the house, explored left and came back, and did this over and over again for tens of minutes because it kept forgetting what it had already done

    • The agent has tools to help it avoid this, like adding things to an external knowledge base, and summarizing what it did to paste into the next context window. But it doesn’t know how to use these very well, perhaps because the model is just using it in ways that seem reasonable, and not in ways that have empirically led to good performance in the past

  • Claude can’t learn new behaviors on the fly. One useful skill humans have is that we can learn certain strategies and high-level actions quickly after only a small amount of experience. But Claude needs to re-learn what to do essentially every time, which makes virtually every task, even ones Claude has done hundreds of times before, have some non-negligible chance of failure. While in principle the external knowledge base can help with this, it doesn’t appear to in practice

  • Claude often has bad in-game decision-making and lacks creativity. While the model often thinks of ideas that seem roughly reasonable given what it knows, it often loses simple opportunities to do things quicker or more easily. It also tends to get stuck with its initial idea (as long as it remembers it) even when something slightly different would work better. For example, at one point Claude decided it wanted to level up its lowest-leveled Pokemon, so every time it died, it took the long walk back to the Pokecenter to heal, even though it would’ve made sense to spend some time leveling up its other low-level characters before making the return trip. Claude sometimes has very good ideas, but because it can’t learn new behaviors on the fly, the good ideas never get reinforced

  All this being said, ClaudePlaysPokemon still impresses me, and is probably the most impressive LLM agent demonstration I’ve seen. Through reasoning and persistence, Claude is able to progress fairly far in the game, accomplish tasks requiring thousands of steps, and eventually get out of loops even when it’s been stuck for a long time. I expect increased agentic RL training, increased cross-context RL training, and test-time learning to iron out a lot of these limitations over the next year or two.

• Kei Nishimura-Gasparian 27 Jan 2025 7:23 UTC

  3 points

  0

  on: Kei’s Shortform

  The setup in the first sketch in Three Sketches of ASL-4 Safety Case Components can be replaced with a classifier that indicates whether a model is doing something catastrophically bad, which corresponds to the high concern features described in the post. Perhaps you can also have a second classifier that indicates if something is moderately bad, which corresponds to the medium concern features.

  If you have such a classifier, you can:

  1. Use it at deployment time to monitor model behavior, and stop the session and read the logs (if allowed by privacy constraints) if the classifier outputs a probability above some threshold

  2. Validate your classifier it by:

  • Running model organisms and see that it is above the threshold whenever the model organism is trying to do something bad and below the threshold when the model is doing something benign

  • Run red-blue games on the entire monitoring methodology

  • Depending on the underlying information fed into the classifier, you may also be able to run observational and interventional studies

  This classifier can leverage any information, SAE vectors or other white box methods as mentioned in the post, the model’s chain of thought, the sequence of actions the model takes, or better yet, all of the above.

Kei’s Shortform