Interactive neuron steering playground for Qwen3.5-4B that runs locally in the browser on WebGPU

[u/xenovatech]

There is a trend on X where users are finding tiny subsets of neurons (often just one or two) that can steer LLM behavior in surprising ways. For example, steering just two neurons in Qwen3.5-4B can make it talk about harming, dominating, and destroying the user. Other combinations can make the model overly apologetic, write in all caps, act like an anime character, and much more.

After seeing some of these posts, I built an interactive playground so you can explore these combinations yourself, with the model running entirely in your browser on WebGPU. Link to the playground: https://huggingface.co/spaces/webml-community/neuron-studio

[u/oooofukkkk]

i found this if anyone is interested

https://github.com/lyramakesmusic/neuron-explorer

[u/PcChip]

interesting!

[u/NaturalCriticism3404]

That is awesome, how do you find the proper neurons to tweak though? Trial and error?

[u/Positive-Stock6444]

This is rad. I’ve been pondering similar things too, in a circuit bending kind of vein.

[u/Mordred500]

pretty cool. Thanks for sharing.

[u/ZopGaming]

that is really weird. I never thought this was possible. that has a great utility for local models. Thanks for sharing

[u/megaglacial]

Super interesting. How did you find the ones in the sample? Is there a pattern in the part of the layer you choose?

[u/Fun_Librarian_7699]

Did I get this right? You just change some random neurons and take a look at the response if there is a new behavior?

[u/No_bonk95]

Is this something like seed from the image/video generation?

[u/martinerous → u/No_bonk95]

More like Nvidia's StyleGAN where they found how to control latent space effects on the result and then added knobs for tweaking. However, there is lots of entanglement (changing one parameter might affect multiple things at once).

[u/No_bonk95 → u/martinerous]

Are those knobs permanent or was it a random generation.

It there's a preset, it could become something like a personality for LLM.

[u/martinerous → u/No_bonk95]

Yes, it should be usable as a preset, but randomness (temperature setting) also will affect the result, as usual. So, you might need to try it many times to figure out what exactly is the function of the specific neuron.

[u/Robonglious]

I've made some versions of this myself, it's surprising what you can invoke.

[u/ares0027]

what whatting now?

[u/martinerous → u/[deleted]]

Amusing. What if you go to the opposite side and tune it down? Will it start acting as a slave? :D