Lasso Research tested SynthID-Text watermarking across six models and found it changes tool-call correctness and weakens refusal under prompt injection. On some models, watermark-induced behavioral churn exceeds what a…
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In your analogy: What if seed 42 specifically causes poor quality behaviour (in some contexts specifically). Normally, these quality differences will be washed out because the seed is random, now it is no longer random, so shouldnt we check into specific behaviour under this specific seed?
My idea would be that the ngram size over which the watermarking works is necessarily limited in order to resist edits better. It might be possible to lead the model to trigger the refusal in the form of these specific ngrams, the completion of which is then more likely flipped to compliance (due to the logit bias introduced by the watermarking), making hazardous requests systematically more likely to be accepted?
Opus 5 started adding a bunch of comments to code, even when instructed not to, and for very simple changes where the comment itself was longer than the code change. Was that so that there are enough tokens outputted for watermarking? Many people suspected so.
Detection of watermarking requires access to the watermarking key, a secret in the current suggested scheme (leaking it would amount to being able to strip the watermark).
So, there will need to be a watermark checking service. The checking service will of course be rate-limited for common folk (and model distillers). OpenAI/Anthropic/Google/other privileged model builders need to filter out AI slop at scale, so need access to others' service without rate-limits (or the watermarking keys need to be shared).
This creates an in-group with pristine datasets, and an outgroup whose models will collapse on the slop outputs with no good ability to filter.
No it's EU law.
Let's say there are four billion possible seeds. There are four billion possible ways we could watermark the generation. We could say "we will choose seed 1, that way we will know exactly what output it produced", we could say "we will choose seed 2, that way we will know exactly what output it produced"... etc etc. Now, if we decide "not to watermark", we STILL must choose a seed. So we are actually still applying one of the watermarks, the only difference is we are not careful to remember which one. Could some seeds give a better or worse answer to some specific prompt? Yes. Could choosing a random "watermark" to apply be better or worse on average than choosing a random seed to apply? No. It's mathematically impossible.
This is like an open source project changing their seed from "12321" to "43", and saying that because we changed the seed, the quality is "necessarily lower".
Take a recurrent PRNG for example. A randomly seeded recurrent function usually has degenerate cycles in its state space. For some functions, this might even describe the majority of the state space. This is why so many non-cryptographic PRNGs are max-cycle, so a different starting point is just further along the same trajectory.
I don't think LLMs have quite the same failure mode here, but recurrence + high dimensional spaces triggers my "here be dragons" sense.
> Relevance and irrelevance are excluded because they test whether a call should be made rather than whether the emitted call is correct.
Relevance and irrelevance are not introduced above this comment. This reads like an LLM-ism (particularly a GPT-ism) editing a document, removing something, and leaving a note about why it was removed, which doesn't really make sense when reading it.
> Their limited movement under prompt injection should therefore not be interpreted as evidence that watermarking preserves safety behavior more reliably on these models.
Also a GPT-ism which appears when it draws a counter-conclusion in the text because it feels the need to be honest and a human tells it to remove it because it's not true because of "reason".
Overall interesting research, however, I think it's great that model output is getting watermarked. I was skeptical of this at first, but Opus 5.5 is so good, it seems like it's a non-issue in practice.
The reason I think watermarking is great is because it's a really good way of preventing training on it's own output indiscriminately and Ouroboros-ing itself.
I just took his text, pasted it to ChatGPT, "rephrase", paste it back in the online checker, 0% AI.
https://chatgpt.com/s/t_6ab7d694885481918083b8cbf0ba9040
In particular: sometimes they measure “churn”, which doesn’t show whether the results are better or worse on average. They sometimes only test with one random seed. There are multiple-comparison issues. And they’re not testing Anthropic’s algorithm.
This is a spy tool.
It's not "watermarking", it's "spymarking": https://news.ycombinator.com/item?id=49794615
You should assume all text is AI generated. If you want to "test" someone at school or during an interview, have them write with a pencil and paper.
This is because SynthID and similar watermarking methods for LLMs don't just change the random seed. They take additional steps (that I have yet to read about) in order to detect when someone changes a few words of the output, trying to remove the watermark.
The other takeaway is that just by knowing a watermark is being applied gives an attacker an advantage in working around safety features because then they know the output isn't based on true randomness and can take advantage of that in a similar fashion to how breaking cryptography becomes easier when the RNG isn't truly random.
If that's the case, then it's a brilliant strategy by the labs to cut down cross-AI usage and just stick to one model. But I'm pretty sure this won't be the case.
As in duck duck go removes Claude watermark..Claude freaks out and puts it back in. Then after a few more times Claude flags all inputs as "prompt injections" and begins offering self deleting code
Read the full thread on Hacker News →
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