s1-jev-cvltist — Model Card

A local, open, Jev-compatible "System One" decision model. s1-jev-cvltist is the name of this release model (project codename "system one", s1; the internal checkpoint id is s1-v6).

Base: Qwen3.5-4B (Apache-2.0) · Adapter: LoRA r=16, α=32 · Context: 4096 Interface: the TypeSafe Jev wire spec (choice / score / noul) · Size: 124 MB adapter Release checkpoint: checkpoints/s1-v6 · Eval holdout: 35,594 frozen rows

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Canonical home: CVLTAI/s1-jev-cvltist — this repo is a personal mirror of that release. Load: PeftModel.from_pretrained(base, "AEECollier/s1-jev-cvltist") over Qwen/Qwen3.5-4B. The full local pipeline (training, eval harness, calibration, serving) lives at github.com/cvlt-ai/decision-model; the adapter here is self-contained (124 MB LoRA + tokenizer).

1. What this is

system one (s1) is a small decision model trained to answer Jev-style questions (choice, score, noul) over a free-form "state", returning calibrated probabilities rather than a bare answer. It is deliberately built on a general instruction base (Qwen3.5-4B) with a thin LoRA adapter, so it carries knowledge a purpose-built encoder can't, while the readout (single-token logit scoring over option keys) keeps inference cheap and the probabilities well-formed.

The design goal was not just to match TypeSafe Jev's accuracy, but to be open and auditable, and to be structurally strong where Jev and its open clones are weak: calibration, negation/invariance consistency, and coverage (knowing when the evidence is insufficient).

2. Task

Given a state (free-form text / structured context) and one or more questions, return a well-formed answer per the Jev wire spec:

Up to 255 options per choice (vendor spec). Answers carry probabilities, not just the top pick — that is what makes calibration and coverage meaningful downstream.

3. Model

• Base: Qwen/Qwen3.5-4B (Apache-2.0, 262k native context).
• Adapter: LoRA (r=16, alpha=32, dropout 0.05) on every attention projection (q/k/v/o) and MLP projection (gate/up/down) plus the gated in_proj modules. ~124 MB. Inference-mode, bf16.
• Readout: LogitReadout (eval/readout.py) — teacher-forces each option key and reads the single-token logit; option keys are scored in chunks (key_batch) to bound peak memory. This is the same NLL proper scoring rule used at training time.

4. Training data

mixture_v6 — 264,162 choice/score/noul rows, 1 epoch, 8,077 optimizer steps (effective batch 32, 4096 context), loss → ~0.06–0.28.

License posture (release line): permissive / commercial-safe. Qwen3.5-4B is Apache-2.0; TSI is the commercial-safe subset; BoolQ is CC-BY-SA and enters only via the --include-sa gate. Non-commercial rows (anli, multi_nli, snli, ai2_arc, hellaswag) are quarantined out of the release mixture.

5. Evaluation — release numbers (full 35,594-row frozen holdout)

Frozen holdout, 9 families, s1-jev-cvltist at 1024 context, T=1.0. This is the citable number (the 300/family sample used during iteration is superseded by the full run).

Per-family accuracy (full holdout)

Strong on six families (≥0.65): injection, banking77, boolq, negation, pubhealth, baserate. The two gaps — go_emotions (0.601, the weakest large family) and mmlu_pro (0.438, the knowledge gap) — are the honest shortfalls.

Calibration

The raw pooled ECE (0.105) is high only because mmlu_pro (12k of 35.5k rows, where the model is genuinely uncertain) dominates the pool — every individual family's raw ECE is fine. Offline temperature scaling (the standard post-hoc phase) at T=1.5 brings pooled ECE to 0.0169 — the best calibration held across any version, well under the 0.03 gate — with Brier 0.1441.

JevBench (public-231, harness's own score_task)

s1-jev-cvltist (coral) is the release checkpoint; s1-v3→v6 is our local progression. openjev (0.814) and Jev 1.13 (0.866) are external, documented numbers, not local runs. Gap to openjev closed from 0.065 to 0.039; Jev 1.13 remains 0.091 ahead.

Evidence-sensitivity (VitaminC flip probe, 200 conflict families)

The broad NLI/counterfactual coverage in the TSI data taught the model to return "not enough info" when the evidence genuinely runs out, instead of forcing an answer — the "don't over-claim" property that is the whole point of a coverage-aware decision model.

6. How it got here (version trajectory, frozen 300/family suite)

* v2's negation spike was a training-data bug (built without BoolQ); fixed in v3. Each line is a deliberate data decision, documented in research/05–research/11. The v6 jump is TSI breadth: it closed most of the knowledge gap and improved the differentiator axes (negation, coverage) simultaneously.

Laya (the purpose-built encoder we set out to beat) is 0.410; s1-jev-cvltist is 0.775 — +0.365 over the encoder baseline, and the largest single jump is the v5→v6 TSI-breadth step.

7. How to run it

Minimal (logit readout, no server):

from eval.readout import LogitReadout
ro = LogitReadout(ckpt="checkpoints/s1-v6", base="Qwen/Qwen3.5-4B",
                  device="cuda:0", temperature=1.5, max_len=1024, key_batch=8)
answers = ro.call(state_text, {"q1": {"type": "choice", "options": {...}}})
# answers["q1"] = {"choice": key, "probabilities": {key: p, ...}}

HTTP (Jev wire spec, src/s1/schema.py speaks the request/response format):

python scripts/serve_s1.py --ckpt checkpoints/s1-v6 --base Qwen/Qwen3.5-4B \
  --device cuda:0 --temperature 1.5 --port 8000
# POST /v1/answer  { "state": "...", "questions": { ... } }

Serving note: LogitReadout + schema.py are the working pieces; serve_s1.py wraps them in FastAPI. There is no batching/continuous-batching layer yet — that is the next serving step if throughput matters.

8. Limitations (honest)

• Knowledge is the gap. mmlu_pro 0.438 vs Jev's documented 0.83. This is the one axis we are clearly behind, and it is bounded by the TSI per-task extraction cap (500/task) which throttled the knowledge-heavy tasks.
• go_emotions 0.601 is the weakest large family — multi-label emotion is hard and it is only in the mix via order-augmentation.
• baserate (n=27) and injection (n=126) are small families; their per-family numbers carry wide confidence intervals.
• Raw pooled ECE is dominated by the uncertain knowledge family; always report the temperature-scaled ECE (0.0169) or per-family ECE, not the raw pool.
• Numbers are from a frozen 9-family holdout + JevBench public-231. They are not measured on Jev's private/internal suites.

9. Reproducibility

• Release checkpoint: checkpoints/s1-v6 (commit 554debd..f9f229e).
• Release eval: results/s1v6_release_full.json (35,594 rows) + results/calibration_s1v6_release.json.
• Build: scripts/train_v6.sh (training), scripts/eval_v6.sh (eval chain), scripts/tsi_extract.py (TSI data).
• Research log: research/01–research/11 (one doc per milestone).
• Frozen holdout: data/holdout/*.parquet + MANIFEST.json (sha256-pinned).

10. License

Base model Apache-2.0; release mixture permissive/commercial-safe (see §4). Adapter weights released under the project license (TBD — see LICENSE).