n8python/gemma-steer

This project, called steerSelf, is a local web app for experimenting with steering vectors on a Gemma language model. A steering vector is a numerical adjustment that is added inside the model while it is running, with the aim of nudging its output toward a chosen trait, like sounding more mystical or more practical. The app comes with a set of these vectors already computed and a way to make new ones. The app is built around a specific Gemma 4 checkpoint hosted on Hugging Face, in an MLX format optimized for Apple Silicon Macs. Two profiles are supported. The full profile uses a 26 billion parameter version of the model at 8 bit precision and is the default. An economy profile uses a smaller 4 bit variant for machines with less memory. Each profile has its own bundle of steering vectors, and the README is clear that these vectors do not transfer cleanly to other models or other Gemma checkpoints. Requirements are macOS on Apple Silicon, Python 3.10 or newer, and 32 gigabytes or more of unified memory for the full profile. Installation is a virtual environment plus a pip install of the requirements file. Running the script steering_webui.py starts a local FastAPI web interface at localhost on port 7860. From the UI, a user can chat with the model, move sliders to apply steering, and open a sampling panel to tweak temperature, top-p, top-k, and similar generation settings. New steering vectors are created from contrastive persona pairs, written one per line as something like cryptic oracle :: practical engineer. The app generates the corresponding dataset, builds the vector, and can hot-load it into the slider list. Vectors and datasets land in profile-specific folders, and custom names cannot collide with built-in axes. A command line script exposes the same vector builder for use outside the web UI, plus a helper to rebuild all bundled vectors for a profile. The repository layout includes the web app scripts, vector builder scripts, the static frontend files, JSON configs for the bundled emotion and style axes, and the vector bundles for each profile. The README is upfront that this is experimental software and that steering vectors should be treated as exploratory controls, not reliable safety edits. The project is released under the CC0 1.0 Universal license.