autotrust/JEV-Gemma4-26B-A4B
An integrated System 1 + System 2 open model on Gemma-4-26B-A4B-it — Decision Index 0.2.1: 58.05
This bundle serves two systems from one set of base weights. System 2 is the unmodified
google/gemma-4-26B-A4B-it (a 26 B-parameter mixture-of-experts model with ≈ 4 B active parameters per token, text and
image input): generation and reasoning, bit-identical to the base model. System 1 adds a LoRA adapter and a 24-slot
decision head and returns calibrated probabilities for three typed primitives in one prefill pass:
noul: true / false
choice: 2–16 options (wider questions are read in groups of ≤ 16 plus a final)
score: 0–5
Two models, two organisations. TypeSafe Jev 1.13 is the hosted, closed model made by TypeSafe AI.
autotrust/JEV-Gemma4-26B-A4B is an independent open-weights model built by AutoTrust AI; it is not affiliated
with, endorsed by, or a product of TypeSafe AI.
Decision Index 0.2.1
Complete run of all 150,759 requests of suite 0.2 (150,317 scored; 0 errors, 0 unsupported), scored with the kit's
score --edition 0.2.1. Results:
autotrust/jev-decision-index-results
(runs/jev-gemma4-26b-a4b).
Engine and read-out
- Template
bare-v1, prefixed with <bos>:
[kind] … [state] … [question] … [options] A) … [decision]:
- Read-out: the final-norm hidden state of the last token goes through a linear fp32 head (hidden 2,816 → 24
slots), soft-capped at 30 like Gemma's own logits; inactive slots are masked, the logits are divided by the per-kind
temperature and softmaxed. Nothing is generated.
- Adapter:
adapter/ is merged into the bf16 backbone in memory at load (as in the Decision Index run).
- More than 16 options: ⌈n/16⌉ contiguous groups read whole, then a final of 16; every option is read, none pruned.
The reference engine for the Decision Index is submissions/jev/jev_engine.py in the
Decision Index kit.
Temperatures
Use calibration_gold.json when you gate automatic actions on confidence.
Usage (transformers + peft)
Training data (disclosure)
System 1 was trained on teacher distributions and ground-truth decision data. The ground-truth data includes the
public training splits of some datasets whose test splits the Decision Index uses; no test split of any
benchmark was used, and suite items were excluded before training. The list has been provided to the Decision Index
maintainers with the submission. MMMU / MMMU-Pro are not valid evaluations for this model.
Limitations
- Where the teacher is wrong, System 1 often is too.
- Weaker than JEV-27B on long structured inputs (e.g. the Decision Index's Home appliance simulator and POP909).
- HLE: below chance, like every open entry on the board; do not use System 1 for expert-level questions.
noul and score accept only their canonical options.
- English-centric; not for high-stakes decisions without confidence gating.
Files
License
Apache-2.0 for the adapter, head and calibration files; base model under the Gemma 4 terms
(https://ai.google.dev/gemma/docs/gemma_4_license). Not affiliated with TypeSafe AI.