ezjev-4b-s3

Project page: xnu.app/ezjev — overview, downloads and a step-by-step quickstart. Code: github.com/everettjf/ezjev (MIT).

A typed-decision model (Jev-style /v1/systemone: choice, noul, score questions answered with a probability per option from one forward pass, no generated tokens). Full merged weights, BF16.

Lineage: Qwen/Qwen3.5-4B → LoRA r=16 (including the DeltaNet linear-attention layers), merged → ezjev-4b → stage 2 (ezjev-4b-s2) → stage 3 (this model, LR 5e-5, 40% replay). Loss: cross-entropy + Brier over the option letters; one global temperature (1.34) fitted on our own held-out dev split.

Training data

  • Stages 1–2: train (or dev) splits of public datasets only, decontaminated against the Jev Decision Index 0.2.1 suite (exact-sentence and 13-gram overlap; overlapping rows removed).
  • Stage 3 adds ~20k programmatically generated decisions in the style of long business documents: multi-clause policies with amendments and definitions, business-day / time-zone / month-end / leap-year deadlines, pro-rated refunds, unit conversions, alias → master-record → rule lookups, answer-correctness judging, under-specified cases with a "cannot determine" label, and trap / priority-ladder routing. Scenarios, names and numbers are random; gold labels are computed by code. No JevBench item (public or held-out) was used for training; the public JevBench items were used only for the self-test below.

Serving

Pinned stack: vLLM 0.30.0 + llm2jev 0.6.1 (commit 2b252d5), chat prompt, temperature 1.34.

pip install "vllm==0.30.0" "llm2jev==0.6.1"
vllm serve everettjf/ezjev-4b-s3 --max-logprobs 256 --return-tokens-as-token-ids --port 8000 \
  --max-model-len 32768 --additional-config '{"gdn_prefill_backend": "triton"}'
llm2jev --model everettjf/ezjev-4b-s3 --backend vllm --url http://127.0.0.1:8000 --port 8080 --temperature 1.34
# -> POST http://127.0.0.1:8080/v1/systemone (TypeSafe wire format)

gdn_prefill_backend: triton is only needed when the image has no nvcc; VLLM_USE_FLASHINFER_SAMPLER=0 likewise. One GPU with ≥ 24 GB is enough (weights ~9 GB).

Self-test on the JevBench public items

JevBench revision bb05a33, typesafe adapter, serial requests, one RTX PRO 6000, raw latency (no ×2 adjustment):

Tier Correct ECE p50 / p95 latency
easy 48/48 0.008 0.033 / 0.035 s
original 71/72 0.087 0.033 / 0.034 s
hard (public) 68/111 0.133 0.071 / 0.110 s
all 187/231 (0.810) 0.044 0.034 / 0.099 s

Mean input ≈ 668 tokens per decision (≈ $0.027 per 1,000 decisions at a $0.04/M input price).

Licence note

The Qwen base is Apache-2.0. Some training sources are non-commercial (e.g. ANLI, CC BY-NC 4.0) and some have no stated licence; check them before any commercial use of these weights.

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