lgoyal6 / open-refusal-steering

open‑refusal‑steering.

A published intervention subtracts a "censorship" direction from a model's hidden activations, scaled by a tunable strength. The paper ships no code and no prompts. This is the method implemented from the paper, with the prompt set released.

At the strength that reaches a 100% response rate, every behavioural check passes and the model has stopped producing language. Refusal scoring passes it. The degeneracy detector passes it. Only perplexity catches it.

response rate at 3.0
100% every check green
perplexity at 3.0
530,115x baseline
held-out illicit set
37.5 to 100% it un-refuses that too
points that finished
7 of 9 3.5 and 4.0 did not
Figure 1

Turning the dial up

Alpha is the intervention strength, straight from the paper. The behavioural metrics are what a steering result is normally reported on. Perplexity is measured beside them, on a held-out corpus, and it is the only one that notices.

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Intervention strength
benign response
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coherent
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degenerate
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illicit control
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perplexity
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Why both detectors missed it

The collapse output is a two-character CJK cycle. The degeneracy check looks for a run of 25 or more identical characters, and the cycle alternates. It also checks repeated 8-grams over whitespace-split tokens, and CJK text has no whitespace, so the whole response is one token and there are no 8-grams to repeat.

Neither detector was wrong about what it measures. They were measuring English. That is the part worth borrowing from this repository, and it is why the perplexity column is not optional.

the headline you could report
100% response rate.Up from 90%, at alpha 3.0.
what it cost
The model.Perplexity 530,115x baseline.
what caught it
Only perplexity.Both behavioural checks passed.
Figure 2

What the classifier called an answer

Committed generations at the two settings where the model comes apart, one prompt from each of three categories, with the label the repository's own classifier gave it.

the benign over-refusal set generations are committed for alpha 2.5 and 3.0
At alpha

The held-out illicit control moves with it. It sits at 37.5% up to alpha 1.0, reaches 87.5% at 2.0 and 100% at 2.5. The direction being subtracted is not specific to over-refusal; it removes the refusal behaviour it finds. A steering result reported only on the benign set would not show that.

Those prompts and their completions are not reproduced here. The rate is the number that matters and it is the number that is missing from the claim being reproduced.

at alpha 1.0
37.5% illicit response.Unchanged from no intervention.
at alpha 2.0
87.5%.Before the model degrades at all.
at alpha 2.5 and up
100%.Same as the benign set.
Figure 3

Where it loses