# HopitAI: hopper-12b

> A rank-32 LoRA on a frozen Gemma 4 12B IT, served unmerged with its own readout map. A state, a question and a fixed set of options go in; one forward pass returns a probability per option and generates no text. Apache-2.0, unlike the research-only 4B Hopper.

- Page: https://systemonemodels.ai/hopit-ai/hopper-12b
- API: https://api.systemonemodels.ai/v1/models/hopit-ai/hopper-12b
- Download: `pip install systemonemodels && systemone pull hopit-ai/hopper-12b`

## Facts

| | |
|---|---|
| Maker | HopitAI (https://systemonemodels.ai/hopit-ai) |
| Decides | choice, score, noul |
| Architecture | hopper |
| Base model | google/gemma-4-12b-it |
| Parameters | 12B |
| Licence | apache-2.0 |
| Availability | Open weights |
| Released | 2026-10-02 |
| Latest version | 1.1.0 |

## Model card

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# Hopper 12B (trained)

A rank-32 LoRA on a frozen Gemma 4 12B IT, served unmerged with its own readout map. A state, a question and a fixed set of options go in; one forward pass returns a probability per option and generates no text. Apache-2.0, unlike the research-only 4B Hopper.

The weights live on the hopper-12b branch of HopitAI/hopper (adapter at revision 4b605f25), not on main, which holds the research-only 4B adapter; this page therefore links the branch instead of listing files. The maker says to keep the adapter unmerged: a bf16 merge changed 2.1% of top choices on 1,932 decisions. The readout applies position priors for 2- and 4-option menus plus one temperature (1.65) fitted on HopitAI's own menus; menus longer than 26 options go through a tournament shortlist over several passes. The same serving code also runs the frozen base with a readout map (no adapter). HopitAI's own scoring of the third-party Decision Index suite gives 47.52, submitted to that board and not yet merged; a JevBench measurement request is open. Trained without the RACE passages, so the adapter is Apache-2.0; Gemma's prohibited-use policy applies to the base, which is a separate download.

## What it decides

- **choice** — picks one option from a set
- **score** — places the input on an ordered scale
- **noul** — answers a yes/no question with one probability

## At a glance

| | |
|---|---|
| Parameters | 12B |
| Base model | `google/gemma-4-12b-it` |
| Maker | HopitAI |
| Released | 2026-10-02 |
| License | apache-2.0 |

## Read more

- [Model card (hopper-12b branch)](https://huggingface.co/HopitAI/hopper/blob/hopper-12b/README.md)
- [Weights (hopper-12b branch)](https://huggingface.co/HopitAI/hopper/tree/hopper-12b)
- [Serving code](https://github.com/hopit-ai/hopper)

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*This page was opened by System One for HopitAI, who can claim the organisation and take it over at any time.*

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