OpenJev general adapter (LoRA, Qwen3-1.7B)

This is the checkpoint to start from. Rank-16 LoRA adapters over Qwen3-1.7B, trained on 279 classification tasks. It answers typed questions about text against a menu of options it has never seen, and it is the recommended OpenJev artifact after the architecture ablation.

Use it zero-shot, on a schema you invent today. If you have a few hundred labels for your task, train a task adapter from the base weights instead of from this one: we measured intermediate initialisation to be worse here, and the numbers are under "Using it as an initialisation".

What it does on schemas it was never trained on

Seven held-out tasks, none in the training mixture, contamination enforced by an automated guard. 600 items each, 95% CIs over 1,000 bootstrap resamples.

Mean 29.6x chance, every task scored at its full advertised menu, which needs --max-len 6144 for the 151-way one. All seven beat chance, and all seven beat their majority-class baseline, including the skewed ones, though helpsteer only just: 0.273 against 0.233 at p = 0.010.

Read the three-digit menus first. Choosing correctly among 151 intents having never seen the label set is the capability that makes this useful. The four-way and five-way rows are honest about the limit: on short sentiment and helpfulness judgements it is better than guessing and not much more.

Honest comparison

We measured TypeSafe's Jev on all seven held-out tasks, 600 items each, the same items this adapter is scored on.

They win five and tie two, and lose none. If you want the best zero-shot accuracy available and you can send your data to an API, use theirs. This adapter is the answer when the data cannot leave your network, when you need determinism or full-precision probabilities, or when you have a few hundred labels, which is the case where a task adapter beats them outright.

Their per-item predictions ship in the repository under baselines/ so the comparison is checkable without an API key.

Quick start

from openjev import DecisionModel, Choice

m = DecisionModel.from_pretrained("s1lv3rj1nx/openjev-general-lora")

q = {"intent": Choice(
    instructions="Which banking intent is this?",
    criteria={"declined_transaction": None, "card_lost": None, "top_up_failed": None},
)}

a = m.answer("my card got declined at the grocery store", q)["intent"]
print(a.label, a.p_max)

a.label is the winning option and a.p_max its probability; a.probabilities is the full distribution over the menu you passed. criteria maps each option to an optional description, so pass None when the label speaks for itself. The menu is model input rather than weights, which is why it can change between calls.

Menus larger than a few dozen options need the sequence budget raised: DecisionModel.from_pretrained(..., max_len=6144) is what the 151-way held-out task was scored with.

The adapter is merged into the base weights at load, which costs 1.07x an unadapted model. Left unmerged it costs 1.96x for nothing, so from_pretrained always merges.

Using it as an initialisation

Do not. We tried it and it is worse than starting from base weights. Initialising the healthcare router adapter from this checkpoint instead of from base Qwen3, trained identically, scores 0.953 against 0.979: paired McNemar p = 0.012, so the intermediate stage costs accuracy rather than buying it.

# Train a task adapter from base weights, not from this adapter.
python scripts/train.py --task tasks/your_task \
  --decoder --lora-r 16 --backbone Qwen/Qwen3-1.7B --epochs 6

The same move on the encoder path was worth +36 points, so this is architecture-specific rather than a general verdict on two-stage fine-tuning (see Phang et al.'s STILTs and Gururangan et al.'s "Don't Stop Pretraining"). The explanation that fits both results: the encoder had to learn what a menu is from a few hundred examples, and base Qwen3 already reads menus from pretraining, so a 279-task specialisation is net interference on one narrow problem.

So: this adapter is for zero-shot use, where there is no task data to train on. It is the wrong starting point when there is.

Training

• 279 tasks, 323,466 rows, curated from tasksource
• Rank-16 LoRA, alpha 32, on all attention and MLP projections
• 1 epoch, batch 8, lr 2e-4, max_len 2048, bf16, one H100, 5.3 hours
• Label-space augmentation: menus padded with distractors, requested up to K=120 from a pool of 670 labels. The context budget of 2048 clipped that to about 80 in practice, so this checkpoint never saw a menu as large as the 151 it is evaluated on.
• Contamination guard asserts no held-out task is in the mixture

Data was audited before training, which mattered more than any architecture change: 3,781 contradictory rows removed, and an ingestion bug that put the gold answer at index 0 in all 83 multiple-choice tasks found and fixed.

Limitations

• English only
• Twenty-one points behind the commercial reference zero-shot on Banking77
• Fine-grained sentiment (sst5) and helpfulness (helpsteer) barely clear their majority baselines
• civil_comments accuracy 0.742 against AUROC 0.828, so the ranking is better than the decision at a 0.5 threshold. Tune the threshold.
• Not a safety classifier. The safety gates in our router only work once trained on that task. Zero-shot, this adapter catches 38% of the clinical cases it should escalate, at a 12% false-positive rate, which is not a gate anyone should deploy.
• Public benchmark scores did not predict readiness on a real task. This adapter wins all seven held-out benchmarks and then loses to the encoder when both are run zero-shot on our healthcare router: intent 0.467 against 0.601. If your task has packed multi-question states, compound multi-label answers or gates with recall floors, measure it yourself rather than reading across from the table above.

Links

• Code, evaluation harness, full results: https://github.com/s1lv3rj1nx/openjev
• Fine-tuned router adapter: https://huggingface.co/s1lv3rj1nx/openjev-router-lora
• Training mixture: https://huggingface.co/datasets/s1lv3rj1nx/openjev-mixture
• Held-out suite: https://huggingface.co/datasets/s1lv3rj1nx/openjev-heldout
• Encoder alternative, 17.2x chance, 20 ms p95: https://huggingface.co/s1lv3rj1nx/openjev-encoder-general

Which OpenJev checkpoint should I use?

Start here. Move to the encoder only if p95 latency binds or the footprint does.