Every answer type-checks. The evidence decides the rest.
A research companion to the first wave of studies on TypeSafe’s Jev and Jev-like models: what their probabilities mean, when software should act on them, and what open implementations actually release.
Jev is a hosted model from TypeSafe AI, released in early access on 15 September 2026 as its first “System One” model. Software sends a text state and typed questions; the model answers from the declared options with probabilities — it never writes free text.
TypeSafe’s hosted Jev, version jev-1.13.0 at the cutoff. Its interface, prices, limits and known failure modes are documented; its architecture, training data and exact confidence statistic are not.
Evidence: black-box evaluations only.
B
The paradigm
Jev-like typed decision models: encoders, frozen or fine-tuned decoders, diffusion reads and adapters that reproduce the request and response shape with other mechanisms.
Evidence: open code and weights, of uneven completeness.
C
The systems
Judges, agents, memory controllers, annotation pipelines and orchestrators whose results depend on typed decisions — plus much else.
Evidence: end-to-end outcomes that need attribution.
DOCUMENTED BY THE VENDOR
Input is text only: a string, JSON object or array of text. Images, audio and video must be converted first.
Versioned IDs; the aliases jev-latest and jev-preview both pointed to jev-1.13.0.
confidence is a statistic computed from the returned distribution; Noul answers carry none.
Calibration is measured over groups of predictions and does not certify an individual answer.
A published list of known failure modes ↗: literal reading, arithmetic, dates, indirection, large states, adversarial text.
Each study is placed where its claim sits on the path from a declared question to a workflow outcome — a frame for comparing evidence, not a model architecture.
01
Decision contract
What exactly is being asked, and what may the answer be?
Visual Jev, REFLEX with Jev, JEV-as-a-Judge, Open-Jev on CallScreenBench and 12 more
SIX RESEARCH QUESTIONS
RQ1
Definition & lineage
How do runtime-defined finite-option decisions relate to classifiers, NLI zero-shot labelling, rerankers, reward models and constrained generation?
RQ2
Probability quality
What do returned probabilities and confidence mean, and for which tasks, languages and distributions do they hold?
RQ3
Efficiency attribution
How much of a speed or cost gain comes from the readout, and how much from backbone size, batching, prefix sharing, caching or the network?
RQ4
Selective control
Which decisions can be delegated, and when should software escalate, abstain or defer to code — judged by end outcome and total cost?
RQ5
Robustness
How do option names, order, rubric binding, missing options, language and distribution shift change decisions?
RQ6
Openness & reproducibility
What do alternatives release — code, weights, data, predictions — and how much of the literature survives a common protocol?
The first wave arrived within a week of launch
Submission dates of the core and peripheral studies (arXiv v1), grouped by their primary relationship to Jev.
Evaluates hosted JevBuilds an independent modelUses Jev inside a systemContext eventPeripheral (dashed ring)
15Sep
Jev released in early access (vendor launch post)
16Sep
17Sep
18Sep
19Sep
20Sep
21Sep
22Sep
23Sep
Submission dates of core and peripheral studies
Date (arXiv v1)
Title
Tier
Primary relationship
19 Sep 2026
Replacing Large Language Models with Jev Decision Models for Low-Latency Edge Service Orchestration
core
Evaluates hosted Jev
19 Sep 2026
Fast Intent-Driven Service Orchestration with Jev for 6G Edge Networks
core
Evaluates hosted Jev
20 Sep 2026
this-that-model-1.0: A typed decision model that decides in 30 ms, for a millionth of a cent
core
Builds an independent model
21 Sep 2026
Open-Jev Judgments on CallScreenBench: Calibrated One-Pass Scam Screening with a Small Language Model
core
Builds an independent model
21 Sep 2026
Jev-Mem: System-One-Controlled Agentic Memory for Efficient AI Agents
core
Uses Jev inside a system
21 Sep 2026
Calibrated Decisions at Scale: Converting Police Crash Narratives into Probabilistic Crash Variables with a System One Model (Jev)
core
Evaluates hosted Jev
21 Sep 2026
JEVQA - Video Quality from Metadata, Bitstream, and Pixel Features with a General-Purpose Decision Model
core
Evaluates hosted Jev
21 Sep 2026
Evaluating Decision Models for Text Annotation in Computational Social Science
core
Evaluates hosted Jev
21 Sep 2026
Jev for Scientific Decisions: Evaluating Semantic Choices and Their Consequences
core
Evaluates hosted Jev
21 Sep 2026
Universal Fractal Natural Language Decision Map: Real-Time Edge Triage Across Heterogeneous Domains
peripheral
Builds an independent model
22 Sep 2026
Visual Jev: Accurate and Efficient Decisions from Shared Visual Context
core
Builds an independent model
22 Sep 2026
REFLEX with Jev for Efficient Selective Control in LLM Agents
core
Evaluates hosted Jev
22 Sep 2026
JEV-as-a-Judge: Accept When Confident, Escalate When Unsure
core
Evaluates hosted Jev
22 Sep 2026
Type-Safe Is Not Error-Free: A Constrained Decision Head Follows the Option Name, Not the Rubric Bound to It
core
Evaluates hosted Jev
23 Sep 2026
JEV-Star: Fast, Low-Cost StarCraft II Control with Language-Model Planning
core
Uses Jev inside a system
23 Sep 2026
KITE: Scaling Jev Population Experiments with Sparse Flagship Calibration
core
Uses Jev inside a system
23 Sep 2026
Can Jev Judge Radiology Reports? Evaluating a System One Model for Clinical Factuality
core
Evaluates hosted Jev
23 Sep 2026
Same Scores, Different Decisions: Evaluating JEV and Language Models for Legal Document Understanding
core
Evaluates hosted Jev
03 THE METHOD ATLAS
Six ways to return a typed answer.
Implementations share the request and response shape, not the mechanism that produces the probabilities. Select a family to see how it works, what is public and where its evidence stops.
A / HOSTED SYSTEM ONE SERVICE
InputText state + typed questions
BackboneUndisclosed hosted model
ReadoutUndisclosed; distribution over the declared options
OutputAnswer + probabilities + confidence
Hosted System One service
A closed, hosted model returns a distribution over declared options for each typed question about a shared text state.
What is public
Interface, primitives, pricing, limits, versioning and known failure modes are documented; architecture, training data and the exact confidence statistic are not.
Where evidence stops
Black-box evaluation only; the served model can change behind aliases; text-only input.
A discrete diffusion LM is seeded with the answer template; after one denoising step, the distribution at each answer slot is read directly.
What is public
Open servers with a Jev-compatible wire API; depends on request extensions proposed in an unmerged vLLM PR.
Where evidence stops
A different mechanism from last-token decoder readout; custom entropy-based confidence.
Representatives
djev (vLLM example server)
OpenJev on DiffusionGemma (razorback16)
REPOSITORIES
mmastrac/djev ↗Readout / adapter / server · DiffusionGemmacode●weights–train○eval○
razorback16/openjev ↗Readout / adapter / server · DiffusionGemma 26B-A4Bcode●weights–train○eval○
STUDIES IN THIS FAMILY
No core study uses this family as its main object.
F / GENERATIVE & CONSTRAINED ADAPTERS
InputPrompt + JSON schema
BackboneGeneral LLM API
ReadoutGenerated (verbalised) probabilities, validated and retried
OutputJev-shaped response
Generative & constrained adapters
A general LLM is asked (often under JSON-schema constraints) to emit a decision and probabilities, which are validated and returned in Jev-shaped responses.
What is public
Wire compatibility for controlled comparisons; probabilities are generated or verbalised, not read from logits.
Where evidence stops
Interface compatibility is not mechanism equivalence; retries, parsing and self-reported probabilities remain.
Representatives
system-one-adapter-python (official, for comparisons)
githubnext/localjev ↗Readout / adapter / server · DiffusionGemma via chat completionscode●weights–train○eval○
STUDIES IN THIS FAMILY
A compatible interface is not an equivalent mechanism. No project here establishes the architecture of the commercial model; several state so explicitly.
04 WHAT THE EVIDENCE SAYS
Findings, with their counter-evidence.
Each finding lists the evidence that supports or qualifies it. Values are as reported by their sources.
F1Valid ≠ correct
A type-valid answer can still be the wrong answer.
Typed interfaces remove parse and schema failures by construction. They say nothing about whether the model read the option the way the author intended: rebinding option names to rubrics, removing an abstain option or asking through a different primitive can move answers while the type-error rate stays at zero.
Supported by
Hosted Jev AUROC .8146 → .5806 after name–rubric swap; 0% type errorsType-Safe Is Not Error-FreeAuthor-reported experiment
Swapping the rubrics behind the option names no/yes changed 32.50% of the hosted model’s answers (neutral names: 2.08% and 1.67%), lowered balanced accuracy from .7127 to .5163 and AUROC from .8146 to .5806.
Limits Hosted model is non-deterministic; observed at one point in time. Contrast 30.42 pts, 95% CI [27.58, 33.33].
Test–retest floor ≤1.33% answer flips; swap = 24× the floorType-Safe Is Not Error-FreeAuthor-reported experiment
Asking the aligned arm twice (300 items × 2 name pairs), the hosted model changed at most 1.33% of answers; the name swap produced 24× that test–retest floor, and at most 36.33% of probabilities repeated bit-for-bit.
Open marker head: AUROC .9376 → .2315 (inversion), 76.92% flipsType-Safe Is Not Error-FreeAuthor-reported experiment
In an open ModernBERT-large marker-readout head, the same swap changed 76.92% of answers against 6.50% behind 0/1 (difference-in-differences 70.42 pts) and inverted AUROC from .9376 to .2315.
Limits This result is for an open checkpoint and must not be attributed to hosted Jev. A mean-pooling span head flips 4.1× less often.
Type-error rate 0% in every condition, by constructionType-Safe Is Not Error-FreeAuthor-reported experiment
The type-error rate was 0% in every condition, including those where decision accuracy collapsed; the paper shows this follows from the renormalised softmax over the declared options (Lemma 1).
Limits A 0% type-error rate is a property of the read-out, so it carries no information about decision quality.
Multi-way: neutral renaming flips 52.42%; accuracy .5637 → .2782Type-Safe Is Not Error-FreeAuthor-reported experiment
On 683 multi-way questions, renaming members to neutral letters without touching descriptions changed 52.42% of answers and dropped accuracy from .5637 to .2782 (open marker head).
Limits Pool accuracy is low (.5637); authors treat the arm as directional.
7 wrong selections changed counts but not the final labelJev for Scientific DecisionsAuthor-reported experiment
Across three comparison models, seven wrong selections on one culture-history question changed downstream counts while preserving the correct final claim label.
Limits Errors were made by comparison models; the point is about evaluation design, not about Jev.
23/30 anchors correct in all 12 responses; 5 consistently wrongJev on Contract InferenceAuthor-reported experiment
On 30 fixed anchors answered twelve times each, Jev kept 23 correct in every response (Claude Sonnet 5: 24; Claude Haiku 4.5: 19). Five of Jev’s anchors received the same wrong label every time, so agreement across repeats overstated correctness.
Limits The Sonnet–Jev difference is one target, with an interval spanning zero. Jev’s output-order condition changes question-key order only.
Abstain removed: acc 0.95 → 0; Noul vs Choice differ by 0.125jujumilk3/jev-calibration-auditCommunity report (repository)
Seven API-only experiments (about 7,000 calls) report that removing the abstain option drove accuracy on unanswerable items from 0.950 to 0.000 at 0.79 confidence, that a Noul and a two-option Choice over the same question differed by 0.125 on average, that 50 identical requests gave 15 distinct answers, and that option order produced no argmax flips in 400 trials.
ECE 0.0204 (CLINC150) vs 0.0936 (Banking77); 0 type errorsjourdanlabs/assay-001Community report (repository)
A pre-registered audit reports Jev’s chosen-option probabilities as calibrated on CLINC150 (ECE 0.0204) but systematically overconfident on Banking77 (ECE 0.0936), with zero type errors across 8,576 responses.
Limits Community report; protocol frozen before queries, per the README.
Noul vs Choice framing reverses the comparison with GPT-4.1jjd-lab/jev-synthetic-surveyCommunity report (repository)
Playing 300 survey respondents, jev-1.13.0 asked through Noul led GPT-4.1 on all six distribution measures, but asked through a two-option Choice it trailed on the distribution gap (0.1985 vs 0.1789): the primitive changes the conclusion.
Limits “Survey” here means a questionnaire study, not a literature review. Community report.
Vendor-listed failure modes for jev-1.13TypeSafe: Jev 1.13 jaggednessVendor documentation
The vendor’s jev-1.13 “jaggedness” page lists known failure modes: literal reading, arithmetic and counting, date comparison, indirection, large irrelevant state, adversarial content, contradictory instructions and criteria, structural invariants, and generation.
Limits A boundary statement by the vendor, not a neutral evaluation.
Random-string names return flips to the neutral regime (2–12%)Type-Safe Is Not Error-FreeAuthor-reported experiment
Replacing option names with random character strings returned flip rates to the neutral-control regime in all three families (6.86%, 11.67%, 2.02%) while aligned balanced accuracy stayed within .03 of the neutral class.
Limits Suggests neutral identifiers as a mitigation; the mitigation itself was not evaluated in deployment.
No type errors by construction; plotted 0% is analyticalTypeSafe: Introducing System One Models & JevVendor documentation
TypeSafe states that Jev never makes type errors because possible outputs are defined in advance, and that its plotted 0% is analytical rather than empirical.
Limits Schema conformance only; says nothing about semantic correctness.
A native probability makes calibration measurable, not guaranteed.
Every call returns a distribution, so reliability can be audited on each run. Measured calibration varies by task and construct, confident errors occur, probabilities are quantised to two decimals, and recalibration fitted on in-distribution labels helps substantially. Calibration is a property to verify per workload, not a certificate.
Supported by
Median ECE 0.157 vs 0.066 for the best (verbalised) LLMDecision Models for CSS AnnotationAuthor-reported experiment
Jev’s median expected calibration error over the evaluation tasks was 0.157 (95% CI [0.108, 0.233]) — lower than the verbalised-confidence error of 16 of 19 LLMs but higher than three frontier Claude models (Opus 5: 0.066).
Limits Median intervals overlap. Under equal-mass binning Sonnet 5 falls slightly behind Jev; Opus 5 stays ahead.
Empathy: confident near chance; task ECE 0.538Decision Models for CSS AnnotationAuthor-reported experiment
On the empathy task the model reported high confidence while performing near chance; the task contributes a calibration error of 0.538, and removing it lowers the median only to 0.142.
Limits One construct; the authors do not claim the failure generalises.
Recalibration on held-out labels cut calibration error ~3.3×Calibrated Decisions at ScaleAuthor-reported experiment
Probabilities ranked well but overstated prevalence until recalibrated; recalibration fitted on half of the human labels reduced calibration error by a factor of about 3.3 (isotonic), with calibration varying by model rather than by paradigm.
Limits Same-distribution labels; not a guarantee for new regions or schemas.
Two-decimal probabilities set a calibration-error floorCalibrated Decisions at ScaleAuthor-reported experiment
Because probabilities are returned on a two-decimal grid, calibration error has a resolution floor for rare variables; the paper derives a bound that applies to any model reporting probabilities on a discrete grid.
JevLite ensemble AUROC .974, ECE .052; no false alarmsOpen-Jev on CallScreenBenchAuthor-reported experiment
A three-seed JevLite ensemble reached AUROC .974 with calibration error .052 on 577 turn-level decisions, non-inferior to an LLM judge (MiniMax-M3) at a pre-registered .02 margin, with no false alarms on legitimate calls and decisions 1.14 turns earlier.
Limits Recipe selection had test-set exposure. All callers synthetic. Fine-tuned ModernBERT not significantly worse.
Raw ECE 0.12; isotonic recalibration → 0.008 on holdoutJev as a Radiology Report JudgeAuthor-reported experiment
Raw sentence-level probabilities had ECE 0.1192 on the ReXErr test set (open NLI: 0.1045); isotonic calibration fitted on half of the studies lowered Jev’s ECE on the other half from 0.1235 to 0.0077.
Limits Calibration fitted and tested on halves of the same benchmark. Measured on the multi-question configuration’s support outputs.
Propagating a fitted human–model discrepancy gave retrospective coverage of 0.93 and 0.96 at nominal 0.80 and 0.90 on 37 unseen studies, against 0.29 and 0.36 from human sampling uncertainty alone.
Limits Retrospective; fitted on studies selected for reliable contrasts.
Abstain removed: acc 0.95 → 0; Noul vs Choice differ by 0.125jujumilk3/jev-calibration-auditCommunity report (repository)
Seven API-only experiments (about 7,000 calls) report that removing the abstain option drove accuracy on unanswerable items from 0.950 to 0.000 at 0.79 confidence, that a Noul and a two-option Choice over the same question differed by 0.125 on average, that 50 identical requests gave 15 distinct answers, and that option order produced no argmax flips in 400 trials.
ECE 0.0204 (CLINC150) vs 0.0936 (Banking77); 0 type errorsjourdanlabs/assay-001Community report (repository)
A pre-registered audit reports Jev’s chosen-option probabilities as calibrated on CLINC150 (ECE 0.0204) but systematically overconfident on Banking77 (ECE 0.0936), with zero type errors across 8,576 responses.
Limits Community report; protocol frozen before queries, per the README.
Spanish state: −3.0 to −6.4 accuracy points on 4 datasetsmarcosmartinez/jev-acentoCommunity report (repository)
With English instructions and a Spanish state, jev-1.13.0 lost 3.0–6.4 accuracy points on all four datasets (XNLI, PAWS-X, MASSIVE, Belebele) across 3,200 paired items and 19,200 calls; ECE roughly doubled on the two hardest tasks.
Limits Community report; pre-registered, per the README.
Unknowable-rule task: temperature ≈3.4 needed; 0.01 quantisationscienthoon/jev-ood-calibrationCommunity report (repository)
On a rule-based task whose label is not recoverable from the text, the chosen level averaged 0.74 probability and a temperature of about 3.4 was needed to make probabilities honest; the returned probabilities were quantised to 0.01 and the gateway exposed no model version.
Limits Unpinned model alias; post-hoc temperature diagnostic.
For a frozen Qwen3-8B on BANKING77 (20-way, 300 items), label-free permutation calibration reduced answer flips under option reversal from 0.230 to 0.073 and ECE from 0.240 to 0.184; with 100–500 labels ECE fell to 0.095 and the share decidable at ≤5% error rose from 7.7% to 52.0%.
Limits Point estimate at n=300; wide interval per README.
Native confidence ~ max probability (Spearman .948–.999)JEV-as-a-JudgeAuthor-reported experiment
Jev’s native confidence had Spearman correlation 0.971, 0.999 and 0.948 with the maximum label probability on RewardBench, JudgeBench and HaluEval, so the authors used max-probability for deferral.
Limits Correlation of rankings, not a description of how confidence is computed.
Confidence = a statistic of the returned distributionTypeSafe: ConfidenceVendor documentation
Choice and Score answers return a probability for every option or level and a confidence value computed from that distribution; Noul answers return only the probability of yes. The documentation calls confidence a convenient statistic and recommends thresholds tested on the user’s own data.
Limits The exact statistic is not specified in the prose; the interactive demo’s formula is labelled as how the demo computes it.
The most consistent use is a bounded first pass with confidence-gated escalation.
Across judging, annotation and agent control, the typed model is usually cheaper and faster but not the most accurate component. Gains appear when uncertain cases are routed to a stronger model or a person, thresholds are chosen on separate data, and cheap generative cascades are included as baselines.
Supported by
RewardBench 92.2% vs 93.5%; HaluEval 87.5% vs 86.7% (GPT-6)JEV-as-a-JudgeAuthor-reported experiment
On RewardBench Jev scored 92.2% against GPT-6’s 93.5% (paired difference −1.25 points, 95% cluster interval [−3.8, 1.5]); on HaluEval 87.5% against 86.7%. Blind adjudication of disagreements put Jev within three points of GPT-6.
Limits Adjudication by one author on disagreement-selected items. Larger gaps on derivation checking and style-adversarial pairs.
JEV-as-a-Judge · §5 (ordinary preference and evidence-grounded factuality)
Frozen two-order cascade: 99% of GPT-6 accuracy at 57% of its feeJEV-as-a-JudgeAuthor-reported experiment
A frozen two-order cascade that accepts confident Jev verdicts and escalates uncertain ones kept 99% of GPT-6’s accuracy at 57% of its fee.
Limits Simulated cascade fees say nothing about real cascade latency. Thresholds chosen on a selection set did not transfer for every fallback.
95% success with 1.12 strong calls/task vs 88% and 4.10 (−72.7%)REFLEX with JevAuthor-reported experiment
At τ = 0.5 REFLEX reached 95% success with 1.12 strong-model calls per task, against 88% and 4.10 calls for the strong-only agent — 72.7% fewer strong calls.
Limits Controlled benchmark shows ceiling effects for 2026 frontier models.
Full semantic correctness; median 0.335 s, p95 0.442 sJev for Scientific DecisionsAuthor-reported experiment
Jev matched five other configurations at complete semantic correctness on 20 Choices × 5 repetitions and had the lowest observed median latency among successful responses (0.335 s; p95 0.442 s), at about $0.000060 per successful response.
Limits Ten cases; six configurations reach complete correctness, so the set is not discriminative.
Low-confidence routing matches the LLM at ¼–½ of its costDecision Models for CSS AnnotationAuthor-reported experiment
Routing low-confidence items to an LLM matched or exceeded that LLM alone at roughly a quarter to half of its measured cost; items at or above 0.9 confidence reached a median accuracy of 0.815 at 0.376 coverage.
Limits Measured on the tested tasks and LLMs only.
No cache: e2e −11.1–25.3%; fees per correct completion −69–71%Replacing LLMs with Jev at the EdgeAuthor-reported experiment
Without caching, median end-to-end latency on requests both systems completed correctly was 11.1–25.3% lower and API fees per correct completion 69.0–70.6% lower; correct on-time completion matched DeepSeek in 7 of 8 conditions and exceeded it in 1.
Limits Caching-disabled conditions only for the latency figure.
Accuracy 77.38% vs 78.96–83.21% for hosted LLMsJev on Contract InferenceAuthor-reported experiment
Baseline accuracy was 77.38% [75.99, 78.81] for Jev against 78.96–83.21% for the seven hosted language models; Gemini 3.5 Flash-Lite gained 5.16 points (paired 95% interval 3.49–6.98) at about six times the cost, while the gain for GPT-5.6 Luna was not established.
Limits Invalid responses count as incorrect for every model. The held-out split does not establish absence from training data.
Kendall τ 0.573 / 0.398 with expert error counts; beats open NLIJev as a Radiology Report JudgeAuthor-reported experiment
A one-question Jev configuration reached Kendall τ 0.573 on RadEvalX and 0.398 on RadEvalExpert with expert total-error counts, exceeding an open NLI judge with the same statements and aggregation; RadMatch on a local 27B model was stronger on clinically significant errors (0.491 vs 0.346 on RadEvalX).
Limits Agreement with reference text, not with the image. Local baselines use a substituted 27B backend.
Flagship anchors covering 1.7% of Epstein states lowered effect MAE from 0.0305 to 0.0180 (paired improvement 0.0125, 95% interval 0.0064–0.0167); on 37 held-out SocSci210 experiments, 0.5–1.5% anchor coverage raised captured decision gain from 0.268 to 0.386.
Limits Preregistered policy-value and heterogeneity primaries were not shown. Corrections can import the flagship’s errors.
Passes content gates in 15/15 new countries; fails intervention gatesKITEAuthor-reported experiment
The Jev kernel passed the content-fidelity gates in all 15 new countries of a 16-country study but failed both intervention-sensitivity gates, which GPT-6 Astra passed.
Limits Models read English in all countries; this does not test multilingual inference.
Jev 0.422 s median; $0.15 of $3.71 per gameJEV-StarAuthor-reported experiment
Median Jev response time was 0.422 s (P95 0.531 s) in full games against 27.60 s for GPT-6 planning calls; of USD 3.71 estimated model cost per game, Jev accounted for USD 0.15 and planning for 96%.
Limits Costs are standard-API-equivalent estimates from recorded usage. Real-time games overlap inference with play.
For a frozen Qwen3-8B on BANKING77 (20-way, 300 items), label-free permutation calibration reduced answer flips under option reversal from 0.230 to 0.073 and ECE from 0.240 to 0.184; with 100–500 labels ECE fell to 0.095 and the share decidable at ≤5% error rose from 7.7% to 52.0%.
Limits Point estimate at n=300; wide interval per README.
Vendor-listed failure modes for jev-1.13TypeSafe: Jev 1.13 jaggednessVendor documentation
The vendor’s jev-1.13 “jaggedness” page lists known failure modes: literal reading, arithmetic and counting, date comparison, indirection, large irrelevant state, adversarial content, contradictory instructions and criteria, structural invariants, and generation.
Limits A boundary statement by the vendor, not a neutral evaluation.
BFCL / τ-style: limited edge over a cheap generative cascadeREFLEX with JevAuthor-reported experiment
On external BFCL tasks and 300 τ-style episodes, advantages over a cheap generative cascade with self-escalation were limited where ordinary routing was already highly accurate.
Limits Held-out validation, not a full leaderboard with multiple trials.
REFLEX with Jev · Abstract; external evaluation; Limitations
Reliability depends on action-set size and near-valid alternativesREFLEX with JevAuthor-reported experiment
Controlled interventions showed that reliability depends on action-set size and on near-valid alternatives near authorisation boundaries.
Limits Effects concentrate in authority and risk families.
Correlation with MOS 0.879 vs P.1204.1 0.898JEVQAAuthor-reported experiment
Against subjective MOS on AVT-VQDB-UHD-1, metadata-only JEVQA reached a correlation of 0.879, close to P.1204.1 (0.898); bitstream statistics did not help.
Limits Standard models have seen part of this database.
Speed and cost claims decompose into different mechanisms and scopes.
Single-request latency, per-question amortized time, batch throughput, end-to-end task time, simulated timing, electricity-only cost and API bills are different quantities. Prefix sharing, batching and caching can explain as much as the readout does. None of the figures can be pooled into a single leaderboard.
Supported by
0.36% of the comparator’s fee; ≈$0.04 per 1,000 judgments at 0.15 sJEV-as-a-JudgeAuthor-reported experiment
Jev’s fee on the latency panel was 0.36% of the strongest comparator’s; the authors summarise it as about $0.04 per 1,000 judgments at 0.15 s.
Limits Fees are estimates from reported usage at collection-time prices, not invoices. One client location, pacing and provider load.
JEV-as-a-Judge · Abstract; §4 (latency and fees); Conclusion
8.9× vs serial, 3.4× vs no-reuse batch; 5.7 ms/question amortizedVisual JevAuthor-reported experiment
With 32 questions per image, shared batched execution was 8.9× faster in warm amortized time than independent serial execution and 3.4× faster than batching that recomputes the prefix (5.7 ms per question; about 182 ms per 32-question batch).
Full semantic correctness; median 0.335 s, p95 0.442 sJev for Scientific DecisionsAuthor-reported experiment
Jev matched five other configurations at complete semantic correctness on 20 Choices × 5 repetitions and had the lowest observed median latency among successful responses (0.335 s; p95 0.442 s), at about $0.000060 per successful response.
Limits Ten cases; six configurations reach complete correctness, so the set is not discriminative.
499,500 narratives screened for $25.23; 195,857 fully codedCalibrated Decisions at ScaleAuthor-reported experiment
A first-stage screen returned answers for 499,500 Texas narratives at a cost of $25.23; the second stage coded 195,857 narratives with a 27-question schema. Cost is governed by schema size rather than narrative length.
$0.000217 electricity per suite pass vs $10.636 for a hosted modelthis-that-model-1.0Author-reported experiment
One pass of the 42-family internal suite cost $0.000217 of electricity (80 W at $0.30/kWh) against $10.636 and 155.2 minutes for the most accurate hosted model measured.
Limits Electricity-only marginal cost excludes hardware, operations and margin; not an API price. Internal suite is not released.
Correct & on time: Jev 459, DeepSeek 463, Qwen 435 of 1,080Intent-Driven 6G Edge OrchestrationAuthor-reported experiment
In the real image-reading service reached over simulated NR access, Jev completed 459 of 1,080 requests correctly and on time, against 463 for DeepSeek and 435 for Qwen.
Limits Faster decisions did not raise completions above DeepSeek. Radio access simulated.
Median client decision latency −15.9% to −26.5%Replacing LLMs with Jev at the EdgeAuthor-reported experiment
Across three consecutive measurement blocks, Jev reduced median client decision latency by 15.9–26.5% against a short structured-output DeepSeek deployment.
No cache: e2e −11.1–25.3%; fees per correct completion −69–71%Replacing LLMs with Jev at the EdgeAuthor-reported experiment
Without caching, median end-to-end latency on requests both systems completed correctly was 11.1–25.3% lower and API fees per correct completion 69.0–70.6% lower; correct on-time completion matched DeepSeek in 7 of 8 conditions and exceeded it in 1.
Limits Caching-disabled conditions only for the latency figure.
$0.000228 and 1.24 s per contract — lowest of ten modelsJev on Contract InferenceAuthor-reported experiment
On the 123-contract baseline Jev had the lowest cost and median response time of the ten configurations: $0.000228 per contract and 1.24 s (P95 1.59 s), against $0.001353 and 1.60 s for Gemini 3.5 Flash-Lite and $0.000931 and 1.74 s for GPT-5.6 Luna.
Limits Costs are token usage times public prices; latency includes network and provider infrastructure. One client; providers and collection times differ.
Under $0.03 per 100 report pairs (judgment calls only)Jev as a Radiology Report JudgeAuthor-reported experiment
One support question per statement kept expert agreement close to the seven-question design with 43–45% fewer input tokens; the judgment calls cost about $0.000226–0.000258 per report pair, under three cents per hundred pairs, excluding local statement extraction.
Limits Priced from token counts at the list price; local decomposition cost excluded.
$0.0227 per 1,000 predictions; median 213 msKITEAuthor-reported experiment
Fresh Jev predictions cost $0.0227 per thousand with median latency 213 ms (p95 304 ms); GPT-6 Astra cost about 312–455 times as much per prediction, and a million agents executed 20 tabulated steps in 0.90 s on a laptop.
Limits Flagship costs are subscription-billed usage converted at list prices. Tabulated execution time excludes fresh inference.
Jev 0.422 s median; $0.15 of $3.71 per gameJEV-StarAuthor-reported experiment
Median Jev response time was 0.422 s (P95 0.531 s) in full games against 27.60 s for GPT-6 planning calls; of USD 3.71 estimated model cost per game, Jev accounted for USD 0.15 and planning for 96%.
Limits Costs are standard-API-equivalent estimates from recorded usage. Real-time games overlap inference with play.
In modeled update scenarios, completion rose by 3.50 and 8.35 percentage points against DeepSeek and Gemini; a direct-attribute Qwen comparison retained a 53.0% latency reduction and a 4.78-point completion gain.
Limits Simulation results; separate from the real-service counts.
$0.042 / M input tokens; 70–500 ms end to end (vendor)TypeSafe: Introducing System One Models & JevVendor documentation
Launch materials report input pricing of $0.042 per million tokens with free output and an end-to-end response time of 70–500 ms, measured from the vendor’s West Coast laptops.
Limits Vendor notes it cannot prove the price is not subsidised. Region- and load-dependent.
193.6× faster, 444.6× cheaper on vendor workflow evalsTypeSafe: Introducing System One Models & JevVendor-reported result
The “193.6× faster, 444.6× cheaper” headline comes from the vendor’s workflow evaluations, whose reference answers average two external frontier models; the vendor expects these to be on the higher end of real-world gains and notes the workflows were written by its capabilities team.
Limits Reference answers are model outputs, not ground truth. Possible selection bias acknowledged by the vendor.
Interface compatibility is not mechanism equivalence.
Open projects reproduce the request and response shape with encoders, frozen or fine-tuned decoders, diffusion reads or prompted generators. Their probabilities come from different mechanisms, they differ in what is released, and none establishes the architecture of the commercial model.
Supported by
Open marker head: AUROC .9376 → .2315 (inversion), 76.92% flipsType-Safe Is Not Error-FreeAuthor-reported experiment
In an open ModernBERT-large marker-readout head, the same swap changed 76.92% of answers against 6.50% behind 0/1 (difference-in-differences 70.42 pts) and inverted AUROC from .9376 to .2315.
Limits This result is for an open checkpoint and must not be attributed to hosted Jev. A mean-pooling span head flips 4.1× less often.
JevLite ensemble AUROC .974, ECE .052; no false alarmsOpen-Jev on CallScreenBenchAuthor-reported experiment
A three-seed JevLite ensemble reached AUROC .974 with calibration error .052 on 577 turn-level decisions, non-inferior to an LLM judge (MiniMax-M3) at a pre-registered .02 margin, with no false alarms on legitimate calls and decisions 1.14 turns earlier.
Limits Recipe selection had test-set exposure. All callers synthetic. Fine-tuned ModernBERT not significantly worse.
68 questions: 0.941 (Brier .042) vs Jev 0.765 (.133); gap = 12 itemsthis-that-model-1.0Author-reported experiment
On a third party’s recorded cohort of 68 questions over 17 states, this-that-model scored 0.941 accuracy (Brier 0.042) against Jev’s 0.765 (0.133); the authors note the 18-point gap rests on 12 questions.
Limits Small cohort; wording chosen by the third party.
2,250 questions: 0.844 vs Jev 0.803 — on the open model’s training shapesthis-that-model-1.0Author-reported experiment
On the 2,250-question subset of the released benchmark every hosted system answered, Jev scored 0.803 against this-that-model’s 0.844 — a comparison the authors call not clean because their model was trained on those question shapes (training moved it from 0.409 to 0.844).
Limits Training-distribution advantage for the open model.
For a frozen Qwen3-8B on BANKING77 (20-way, 300 items), label-free permutation calibration reduced answer flips under option reversal from 0.230 to 0.073 and ECE from 0.240 to 0.184; with 100–500 labels ECE fell to 0.095 and the share decidable at ≤5% error rose from 7.7% to 52.0%.
Limits Point estimate at n=300; wide interval per README.
Same weights for all accounts; architecture undisclosedTypeSafe: Models (Jev 1.13)Vendor documentation
Jev is not fine-tuned or LoRA-adapted with customer data; it is trained with RLCD and the same weights serve every account. Architecture and training data are not documented.
Wire-compatible, not a logit read: probabilities are generatedgithubnext/localjevCode/README inspection
LocalJev returns Jev-shaped responses by asking a model for JSON probabilities, validating, retrying and normalising them; its README states this is wire-compatible but not mathematically equivalent to a logit read.
Reproduces the interface pattern, not Jev’s model or trainingTheoLeeCJ/SemIfCode/README inspection
SemIf (formerly OpenJev) reproduces the interface pattern with a frozen open model’s option-token probabilities and states that it does not reproduce Jev’s undisclosed model or training.
Architecture follows third-party speculation, not a disclosurejaredpalmer/kevCode/README inspection
Kev states that it follows an architecture described in a third-party blog post about Jev; that description is community speculation, not a disclosure by TypeSafe.
Text-only input; English is the primary training languageTypeSafe: Models (Jev 1.13)Vendor documentation
jev-1.13.0 accepts text only (a string, JSON object or array of text values); images, audio and video must be pre-processed into text or structured fields. English is the primary training language.
Limits Visual Jev and JEVQA do not change this: one is an independent model, the other feeds text features.
System-level gains need module-level attribution and the right reference.
Memory systems, orchestration pipelines and scientific workflows improve for many reasons at once. Attribution requires ablations, matched baselines and references that measure what the workflow reuses (derived quantities, narrative-grounded labels) rather than only final labels.
Answer-supervised post-training raised equal-weight macro accuracy across four benchmarks from 0.706 to 0.761, with the gain concentrated on the two task families represented in training.
Limits Seen-family gains; limited transfer to unseen families.
7 wrong selections changed counts but not the final labelJev for Scientific DecisionsAuthor-reported experiment
Across three comparison models, seven wrong selections on one culture-history question changed downstream counts while preserving the correct final claim label.
Limits Errors were made by comparison models; the point is about evaluation design, not about Jev.
PLCC vs VMAF: 0.737 (metadata) → 0.824 (+bitstream, pixel)JEVQAAuthor-reported experiment
Against VMAF, metadata-only JEVQA reached PLCC 0.737 (ITU-T P.1204.1: 0.733); adding bitstream data gave 0.797 and bitstream plus pixel features 0.824; a pixel-only variant failed.
Limits Target is VMAF, not human MOS. Trained models on the same features remain clearly ahead.
On LoCoMo, Jev-Mem reached an overall LLM-as-a-Judge score of 0.777 (+11.0% relative to the strongest baseline), built memory in 158 s (6.6× faster than the fastest competing memory system) and averaged 0.93 s per query (36.7% lower than the fastest memory baseline at 1.47 s).
Limits Gains belong to the whole system; each number has a different baseline; LLM-judge metric.
Correct & on time: Jev 459, DeepSeek 463, Qwen 435 of 1,080Intent-Driven 6G Edge OrchestrationAuthor-reported experiment
In the real image-reading service reached over simulated NR access, Jev completed 459 of 1,080 requests correctly and on time, against 463 for DeepSeek and 435 for Qwen.
Limits Faster decisions did not raise completions above DeepSeek. Radio access simulated.
Flagship anchors covering 1.7% of Epstein states lowered effect MAE from 0.0305 to 0.0180 (paired improvement 0.0125, 95% interval 0.0064–0.0167); on 37 held-out SocSci210 experiments, 0.5–1.5% anchor coverage raised captured decision gain from 0.268 to 0.386.
Limits Preregistered policy-value and heterogeneity primaries were not shown. Corrections can import the flagship’s errors.
4/4 full-game wins incl. two vs Lv7 with GPT-6 plans; Jev-only never expandedJEV-StarAuthor-reported experiment
With GPT-6 plans, the controller won all four completed non-cheating full games, including two against Lv7; the earlier Jev-only controller reached its 20-minute limit against Lv2 without ever expanding.
Limits The two controllers also differ in candidate descriptions and execution handling. Opponents are not matched between controllers.
Across 35 SMAC-Hard maps with three episodes each, the combined system raised mean enemy elimination from 16.50% to 37.69% and wins from 3 to 7 out of 105.
Limits One shared plan per map; the three episodes are not independent planner samples.
The evidence base is young, clustered and unreplicated.
The core preprints appeared within five days of one another, most as a single version; two share a study family; many community results are self-reported; several comparisons rest on a handful of items or on test-set-informed choices. None of the core results has been independently reproduced.
Supported by
Test–retest floor ≤1.33% answer flips; swap = 24× the floorType-Safe Is Not Error-FreeAuthor-reported experiment
Asking the aligned arm twice (300 items × 2 name pairs), the hosted model changed at most 1.33% of answers; the name swap produced 24× that test–retest floor, and at most 36.33% of probabilities repeated bit-for-bit.
68 questions: 0.941 (Brier .042) vs Jev 0.765 (.133); gap = 12 itemsthis-that-model-1.0Author-reported experiment
On a third party’s recorded cohort of 68 questions over 17 states, this-that-model scored 0.941 accuracy (Brier 0.042) against Jev’s 0.765 (0.133); the authors note the 18-point gap rests on 12 questions.
Limits Small cohort; wording chosen by the third party.
2,250 questions: 0.844 vs Jev 0.803 — on the open model’s training shapesthis-that-model-1.0Author-reported experiment
On the 2,250-question subset of the released benchmark every hosted system answered, Jev scored 0.803 against this-that-model’s 0.844 — a comparison the authors call not clean because their model was trained on those question shapes (training moved it from 0.409 to 0.844).
Limits Training-distribution advantage for the open model.
Self-reported 92.6% macro-accuracy, 7.08 ms on CPU, “#1” on JevBenchUniversal Fractal Decision MapAuthor-reported experiment
The authors report 92.6% macro-accuracy (95% CI 90.8–94.1%) on their own corpus of 1,150+ decisions, a 7.08 ms median latency on commodity CPU and a first-place result (81.65%) on the community JevBench board.
Limits Self-reported; leaderboard claim relies on a community submission.
“0% bypass” with a 95% interval up to 30.8%Universal Fractal Decision MapAuthor-reported experiment
The reported 0.0% empirical prompt-injection bypass carries a 95% Wilson interval of 0.0–30.8%, which implies a very small number of evaluated vectors.
Unknowable-rule task: temperature ≈3.4 needed; 0.01 quantisationscienthoon/jev-ood-calibrationCommunity report (repository)
On a rule-based task whose label is not recoverable from the text, the chosen level averaged 0.74 probability and a temperature of about 3.4 was needed to make probabilities honest; the returned probabilities were quantised to 0.01 and the gateway exposed no model version.
Limits Unpinned model alias; post-hoc temperature diagnostic.
193.6× faster, 444.6× cheaper on vendor workflow evalsTypeSafe: Introducing System One Models & JevVendor-reported result
The “193.6× faster, 444.6× cheaper” headline comes from the vendor’s workflow evaluations, whose reference answers average two external frontier models; the vendor expects these to be on the higher end of real-world gains and notes the workflows were written by its capabilities team.
Limits Reference answers are model outputs, not ground truth. Possible selection bias acknowledged by the vendor.
Aliases point to jev-1.13.0; pin versions when tuning thresholdsTypeSafe: Models (Jev 1.13)Vendor documentation
Aliases jev-latest and jev-preview both pointed to jev-1.13.0 at the time of review; the vendor advises pinning the versioned ID when thresholds were tuned to a specific version.
How reported failures arise. Illustrative panels use hand-made numbers; Reported panels show published values with their source.
Illustrative
Keep the rubric. Move the name.
Each option is a name plus a rubric that defines it. The study behind this panel changes only which name sits in front of which rubric; question, state, rubric wording and the set of names stay byte-identical.
noThe request does not meet the refund policy.
yesThe request meets the refund policy.
Names and rubrics as the task ships them.
Reported
What the swap did (n = 1,200)
AUROC as shippedAUROC after name–rubric swap
32.50% of hosted answers flipped vs ~2% under neutral names; 24× the test–retest floor.
Type-error rate: 0% in every arm — by construction.
Random-string names: flips fall back to the neutral regime.
Order swaps are a different test: one community audit saw 0 argmax flips in 400 on hosted Jev.
Choice answers return a probability per option; “confidence” compresses that shape into one number. Move the sliders: different summaries disagree about how sure the same distribution is.
Reported
What is known about Jev’s confidence
The vendor documents it as a statistic of the returned distribution; Noul answers have none.
Its exact formula is not stated in prose. The documentation’s interactive demo shows one normalised max-probability formula, labelled as how the demo computes it.
In one study, native confidence ranked items almost exactly like the maximum label probability (Spearman 0.948–0.999).
A community audit read confidence as a probability of being correct and found ECE 0.035–0.18 depending on the dataset.
Bin predictions by confidence and compare with how often they were right. The curves are hand-made to show three regimes; they are not Jev measurements.
Reported
Measured calibration varies by task
Setting
Reported
Source
CSS annotation, 15 tasks
Median ECE 0.157 vs 0.066 for the best (verbalised) LLM
Different datasets, bins and metrics: read each row on its own; do not average across rows.
Illustrative
A typed answer must pick something.
If the right answer is not among the options, the distribution still sums to one. Toggle the abstain option to see where the probability mass goes.
Reported
Removing the exit
A community audit removed the “unknown” option from an unanswerable benchmark: accuracy on those items went from 0.950 to 0.000, with 0.79 confidence and a stereotype rate rising from 0.03 to 0.79.
Forced forms invite invented answers in generative models too (PhantomFill, background).
The vendor lists contradictory instructions and indirection among known weak spots.
Reordering options and rebinding names test different things: one community audit found no argmax flips under order changes on hosted Jev, while frozen open readouts are order-sensitive until calibrated.
Mitigation Report order permutation and name rebinding as separate arms.
When the correct answer is not among the options, a typed model must still choose; removing an abstain option collapsed accuracy on unanswerable items at high confidence.
Mitigation Include an explicit unknown/abstain option and test with it removed.
When comparing with generative baselines, parse failures and repairs change accuracy independently of reasoning; typed outputs remove the failure but not the confound in comparisons.
Mitigation Count invalid outputs as errors and report parse rates separately.
The vendor lists literal reading, arithmetic and counting, date comparison, indirection, large irrelevant state, adversarial content and contradictory criteria as known weaknesses.
Mitigation Keep arithmetic and date logic in code; filter state; split indirect questions.
Across judging, annotation and agent control the typed model is usually the cheapest and fastest component, and rarely the most accurate. Reported gains come from routing uncertain cases elsewhere — with thresholds set on separate data.
Illustrative · synthetic scores
How a threshold spends the escalation budget
A cheap typed model answers every item and reports a confidence; items below the threshold τ go to a strong model assumed correct 95% of the time and 50× more expensive. The data are simulated to show the trade-off, not measured.
Model judging
Model test
The typed model decidesWhich of two responses is better, or whether an answer is supported.
RewardBench 92.2% vs 93.5%; HaluEval 87.5% vs 86.7% (GPT-6)
Frozen two-order cascade: 99% of GPT-6 accuracy at 57% of its fee
Kendall τ 0.573 / 0.398 with expert error counts; beats open NLI
Caution Derivation checking and style-adversarial pairs remain hard; adjudication by one author.
Annotation & coding
Model test · System test
The typed model decidesLabels for social-science text and crash narratives, with a probability per label.
Behind best LLM on 14/15 tasks (−11.6 F1) at 44× lower cost
Low-confidence routing matches the LLM at ¼–½ of its cost
F1 0.908 vs 2,416 human judgments; one frontier LLM +0.059
Recalibration on held-out labels cut calibration error ~3.3×
Caution Per-construct failures; recalibration fitted on in-distribution labels.
Agent control
System test
The typed model decidesWhich tool or action to take next inside an agent, escalating to a strong LLM when unsure.
95% success with 1.12 strong calls/task vs 88% and 4.10 (−72.7%)
BFCL / τ-style: limited edge over a cheap generative cascade
4/4 full-game wins incl. two vs Lv7 with GPT-6 plans; Jev-only never expanded
Caution A cheap generative cascade is competitive where routing is already accurate.
Agent memory
System test
The typed model decidesHow memories are typed, routed, budgeted, traversed and when retrieval stops.
Passes content gates in 15/15 new countries; fails intervention gates
Caution Fails intervention-sensitivity gates without flagship anchors; two human-referenced tests.
07 THE OPEN ECOSYSTEM
“Open” is six different things.
Code, weights, training recipes, evaluation material, data and raw predictions are separate properties, released separately. “Not located” does not mean absent.
● Available◐ Partial◑ Restricted◔ Project page only○ Not located– Not applicableLicence is the field GitHub detects; NOASSERTION means “not identified”, not “no licence”.
STUDY FAMILY
Intent-Driven 6G Edge Orchestration · Replacing LLMs with Jev at the Edge
Same author group (Li, Wang, Gong, Lang, Yu) and related edge service paths; synthesise as one family, not two independent replications.
DERIVED FROM
FLock-io/this-that-model → Mapika/decider
this-that-model-1.0 is adapted from decider-2b (Apache-2.0), per the paper’s Availability section.
USES RESOURCES FROM
this-that-model-1.0 → TianyuCodings/NanoJev
Environment simulator and the recorded hosted-service cohort (68 questions) come from NanoJev (MIT).
COMPATIBLE, NOT EQUIVALENT
githubnext/localjev → razorback16/openjev
LocalJev states it is wire-compatible but not mathematically equivalent to OpenJev’s logit read.
SAME NAME, DIFFERENT THING
“RLCD”
TypeSafe’s “Reinforcement Learning for Calibrated Decisions” is unrelated to “RLCD: Reinforcement Learning from Contrastive Distillation” (2023); 2609.24574 makes the same distinction. Neither adjacency implies the same algorithm or copying.
SAME NAME, DIFFERENT THING
“OpenJev”
Three different things: SemIf (formerly OpenJev, frozen-decoder readout), razorback16/openjev (DiffusionGemma server) and the “Open-Jev” title of 2609.23959 (JevLite).
SAME NAME, DIFFERENT THING
“REFLEX”
The agent architecture of 2609.26532 is not any community project named “reflex”.
SAME NAME, DIFFERENT THING
“Visual Jev”
An independent research model (2609.25845), not a TypeSafe release; hosted Jev is text-only.
SAME NAME, DIFFERENT THING
“System One / System 1”
TypeSafe’s product category borrows Kahneman’s System 1 metaphor; System-1/2 reasoning literature (e.g. 2502.17419) predates and is broader than the product.
08 THE READING ROOM
Search the evidence.
Filter by stage, method family, relationship to Jev or openness, and open any record for its evidence.
With GPT-6 planning, the controller won all four completed non-cheating games, including two against Lv7, at a median Jev response of 0.422 s and about USD 3.71 per game (USD 0.15 for Jev); across 35 battle maps mean enemy elimination rose from 16.50% to 37.69% and wins from 3 to 7 of 105.
arXiv preprint23 Sep 2026CodePredictions (partial)AgentsEfficiency & costSelective control
Flagship anchors covering 1.7% of states cut Epstein effect error by 41% (MAE 0.0305 → 0.0180), and 0.5–1.5% anchor coverage raised captured decision gain on 37 held-out SocSci210 experiments from 0.27 to 0.39; Jev alone passed content-fidelity gates but failed the intervention-sensitivity gates.
A one-question Jev configuration reached Kendall τ 0.573 (RadEvalX) and 0.398 (RadEvalExpert) with expert error counts, above an open NLI judge in the same pipeline, at under US$0.03 per 100 report pairs for the judgment calls; RadMatch on a local 27B model agreed better on clinically significant errors.
arXiv preprint23 Sep 2026Code not locatedJudging & rewardCalibrationEfficiency & cost
Jev had the lowest cost ($0.000228 per contract) and median response time (1.24 s) but lower baseline accuracy (77.38%) than all seven hosted language models (78.96–83.21%). On 30 fixed anchors it kept 23 correct in all twelve responses, one fewer than Claude Sonnet 5, while five of its anchors were answered wrongly every time.
Post-training raised equal-weight macro accuracy from 0.706 to 0.761; with 32 questions per image, shared batched execution was 8.9× faster (warm, amortized) than independent serial calls and 3.4× faster than batching that recomputes the prefix.
At threshold τ = 0.5, REFLEX reached 95% success with 1.12 strong-model calls per task, against 88% and 4.10 calls for the strong-only agent (72.7% fewer strong calls).
arXiv preprint22 Sep 2026Code not locatedAgentsSelective controlEfficiency & cost
On ordinary preference and evidence-grounded factuality Jev stayed within three points of the strongest judge (GPT-6 Astra) at 0.36% of its fee; a frozen two-order cascade kept 99% of GPT-6’s accuracy at 57% of its fee.
arXiv preprint22 Sep 2026Code announced, not foundJudging & rewardSelective controlCalibration
Rebinding the rubrics behind no/yes lowered hosted Jev’s AUROC from .8146 to .5806 and flipped 32.50% of its answers (neutral names: ~2%; 24× its test–retest floor) while type errors stayed at 0%. The steeper .94→.23 inversion comes from an open marker head, not from Jev.
arXiv preprint22 Sep 2026Code announced, not foundInterface semanticsRobustnessOpen implementations
A three-seed ensemble reached AUROC .974 with calibration error .052, non-inferior to an LLM judge at a pre-registered .02 margin, with no false alarms on legitimate calls and decisions 1.14 turns earlier; 64.5 ms per decision on one consumer GPU, 4.9× faster than the same backbone fine-tuned to generate.
arXiv preprint21 Sep 2026Code not locatedOpen implementationsCalibrationEfficiency & cost
LLM-as-a-Judge 0.777 on LoCoMo (+11.0% relative to the strongest baseline), memory construction in 158 s (6.6× faster than the fastest competing system) and 0.93 s average query latency (36.7% lower).
Against human labels the typed model reached F1 0.908; one frontier model was 0.059 higher and the other indistinguishable. Probabilities ranked well but overstated prevalence; recalibration on the same labels cut calibration error about 3.3×.
With metadata only, JEVQA reached PLCC 0.737 against VMAF (P.1204.1: 0.733), rising to 0.797 with bitstream data and 0.824 with bitstream plus pixel features; against MOS it reached 0.879 (P.1204.1: 0.898).
arXiv preprint21 Sep 2026Code not locatedMultimodal inputsEvaluation methodology
Jev trailed the per-task best LLM on 14 of 15 tasks (median −11.6 macro-F1) at a median 44× lower measured cost. Its median ECE (0.157) beat the verbalised confidence of 16 of 19 LLMs but not three frontier Claude models (best 0.066). Routing low-confidence items to an LLM matched or exceeded the LLM alone at a quarter to half of its cost.
Jev matched five other configurations at complete semantic correctness and had the lowest observed median latency among successful responses (0.335 s; p95 0.442 s). Seven wrong selections by comparison models changed downstream counts while leaving the final label correct.
arXiv preprint21 Sep 2026Code not locatedEvaluation methodologyEfficiency & cost
30.9 ms per decision on one laptop GPU; on the 68-question cohort 0.941 accuracy (Brier 0.042) against Jev’s 0.765 (0.133); on the 2,250-question subset 0.844 against Jev’s 0.803.
Jev cut median client decision latency by 15.9–26.5%. Without caching, end-to-end latency on requests both systems completed correctly was 11.1–25.3% lower and API fees per correct completion 69.0–70.6% lower; correct on-time completion matched DeepSeek in 7 of 8 conditions and exceeded it in 1.
arXiv preprint19 Sep 2026Code not locatedEfficiency & costStructured output
With correct interpretation on all evaluated contracts, Jev cut median decision latency by 22.4% against DeepSeek and 61.9% against Gemini. In the real image service over simulated NR access it completed 459 of 1,080 requests correctly and on time, against 463 for DeepSeek and 435 for Qwen.
arXiv preprint19 Sep 2026Code not locatedEfficiency & costAgents
Author-reported 92.6% macro-accuracy (95% CI 90.8–94.1%) on 1,150+ decisions, 7.08 ms median latency on CPU, and a first-place claim on the community JevBench board (81.65%).
Sai Babu Udayagiri, Arjun Chouhan, Ravisekhar Kanagala et al.
A cheap stacked ensemble that escalates only its least-confident predictions to an LLM; on IEMOCAP the ensemble alone beat every LLM configuration — trained cheap models are the first baseline for escalation designs.
Answer-level reliability scores built from option-probability lists can be refined under target shift, without changing answers, when a labelled target pilot exists.
In synthetic survey panels the response contract (committed sets vs per-option probabilities) dominates measured fidelity — the same interface dependence seen with Noul vs Choice.
Conformal coverage calibrated in isolation breaks under a score-mechanism shift (peer pressure); an attacker can target the low-confidence items a gate still covers.
Under domain shift the ranking of confidence signals changes: whole-output probability is the best in-domain error detector but degrades out of domain.
arXiv preprint20 Aug 2026CalibrationSelective controlRobustness
Format recovery can masquerade as reasoning gains; grammar-constrained decoding closes much of the gap, so parseability must be separated from content when typed and generative outputs are compared.
arXiv preprint5 Aug 2026Structured outputEvaluation methodology
Entity binding failures — the right tool acting on the wrong entity — separate tool correctness from entity correctness, a close analogue of option-name binding.
arXiv preprint29 Jun 2026Interface semanticsAgentsSelective control
KaLM-Reranker-V1: a reranker whose updated abstract links a Jev model collection; that link does not make it a Jev source paper. Full text spot-checked.
arXiv preprint22 Jun 2026ClassificationEfficiency & cost