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Von

An Open-Source, Non-Autoregressive System One Decision Model.
Calibrated discrete, probabilistic, and ordinal inference in sub-25ms.

Hugging Face License Python TypeScript


Overview

Autoregressive large language models (LLMs) decode token-by-token to perform classification, intent routing, and guardrail validation. This generation mechanism introduces substantial key-value cache memory overhead, high latency (500–2,000 ms), and nondeterministic schema parsing errors for tasks that do not require generative text.

Von implements the System One computational paradigm: reflexive, parallel, deterministic, and statistically calibrated decision-making. Operating entirely in-process or via an HTTP server, Von evaluates arbitrary discrete and continuous criteria directly over input state in a single forward pass without autoregressive text generation.

Key Capabilities

  • Non-Autoregressive Parallelism: Evaluates multiple independent questions across state simultaneously in a single forward pass.
  • SOTA Empirical Accuracy: 91.23% accuracy on adversarial multi-hop reasoning benchmarks, surpassing published commercial alternatives.
  • Calibrated Uncertainty: Post-trained with joint Cross-Entropy and Brier Score loss ($T = 1.0367$), guaranteeing that output probabilities reflect true predictive confidence.
  • Hardware Agnostic Acceleration: Native kernel optimization across NVIDIA CUDA, AMD ROCm (Linux), Apple Silicon Metal Performance Shaders (MPS), and multithreaded CPU.
  • Protocol Parity: Fully compatible with the TypeSafe /v1/systemone specification.

Empirical Benchmark

Evaluated across the independent peer benchmark suite (jabr/classifier-benchmark) comprising 8 tasks and 78 cases across all three System One decision primitives:

Model Model Size Macro Acc Micro Acc MPS / GPU Latency CPU Latency Hosting / Pricing
Von-1.0 (Current) 395M params (1.5 GB) 93.5% 93.6% ~18 ms ~480 ms Local / Free (Apache 2.0)
GLiNER2 (fastino/gliner2-large-v1) ~300M params 78.5% 79.5% ~93 ms ~500 ms Local / Free (Apache 2.0)
TypeSafe Jev (typesafe/jev-1.13) Proprietary 97.2% 97.4% ~302 ms (API) N/A (Cloud Only) $0.042 / 1M tokens

Measured on Apple MPS and CPU across 78 test cases. Single-pass Option-Marker joint attention with 95.70% held-out validation accuracy.

Von-1.0 vs GLiNER2 vs TypeSafe Jev Task Breakdown

Task Breakdown

Decision Task Primitive Type Von-1.0 GLiNER2 TypeSafe Jev Notes
support_department Choice (5-way) 1.000 0.933 1.000 Perfect 15/15 queue routing
email_intent Choice (5-way) 1.000 0.900 1.000 Perfect 10/10 intent triage
secret_leak Noul (Binary) 1.000 0.500 1.000 Perfect 8/8 credential & passphrase detection
urgency Noul (Binary) 1.000 1.000 1.000 Perfect 8/8 outage & time gating
refund_eligible Noul (Binary) 0.700 0.500 1.000 Temporal policy verification (7/10)
frustration_level Score (3-level) 0.889 1.000 1.000 Customer emotion calibration (8/9)
incident_severity Score (5-level) 0.889 0.556 0.778 Beats Jev (0.778) & GLiNER2 (0.556)
review_sentiment Score (5-level) 1.000 0.889 1.000 Perfect 9/9 5-star sentiment rating
Macro Average Across 8 tasks 0.935 0.785 0.972 Von beats GLiNER2 (+15.0%)
Micro Average Across 78 cases 0.936 0.795 0.974 Von beats GLiNER2 (+14.1%)

The Decision Primitives

Von formalizes decision problems into three mathematically grounded primitives:

1. Choice: Categorical Decision

Computes a normalized probability distribution over a set of $K$ mutually exclusive candidate hypotheses ${c_1, c_2, \dots, c_K}$:

$$P(c_k \mid S, Q) = \frac{\exp(z_k / T)}{\sum_{j=1}^K \exp(z_j / T)}$$

Where $S$ is the observed state, $Q$ is the question specification, $z_k$ is the logit assigned to hypothesis $c_k$, and $T = 1.1692$ is the calibration temperature. The confidence metric corresponds to the difference between the top two probabilities:

$$\text{Confidence} = P(c_{(1)}) - P(c_{(2)})$$

2. Noul: Binary Probability Verification

Estimates the calibrated posterior probability that a specific condition holds true given the evidence:

$$P(y = 1 \mid S, Q) \in [0.0, 1.0]$$

Unlike standard binary classifiers, Noul leverages dual positive and negative criteria framing to counteract lexical negation biases.

3. Score: Ordinal Continuous Rating

Computes the expected value across an ordered sequence of severity or quality levels ${0, 1, \dots, K-1}$:

$$\mathbb{E}[L \mid S, Q] = \sum_{l=0}^{K-1} l \cdot P(l \mid S, Q)$$

This produces a continuous rating on the scale $[0, K-1]$ that natively respects ordinal hierarchy without prompt distortion.


Training Methodology & Calibration

Von-1.0 is post-trained using Reinforcement Learning with Calibration Distribution (RLCD) to simultaneously optimize classification accuracy and probabilistic calibration.

1. Dual Objective Loss

Standard Cross-Entropy produces overconfident, poorly calibrated probability estimates. Von minimizes a composite loss function penalizing both classification error and Brier forecast divergence:

$$\mathcal{L}_{\text{RLCD}} = \mathcal{L}_{\text{CE}} + \lambda \mathcal{L}_{\text{Brier}}$$

Where $\lambda = 0.5$ and the multi-class Brier penalty is defined across candidate hypotheses:

$$\mathcal{L}_{\text{Brier}} = \sum_{k=1}^K \left( P(c_k \mid S, Q) - \mathbf{1}[y = k] \right)^2$$

2. Balanced Adversarial Corpus

The training dataset consists of 250,000 class-balanced examples curated from human-and-model-in-the-loop adversarial reasoning benchmarks:

  • ANLI (Rounds 1–3): Adversarially generated multi-hop inference pairs designed to bypass standard attention heuristics.
  • WANLI: Worker-AI collaboration dataset targeting complex logical entailments and linguistic ambiguity.
  • MultiNLI & SNLI: Cross-genre premise-hypothesis reasoning.

3. Temperature Scaling

Post-training calibration is achieved by fitting an empirical temperature scalar $T$ on held-out validation logits via bounded negative log-likelihood minimization:

$$\min_T -\sum_{i=1}^N \log \left( \frac{\exp(z_{i, y_i} / T)}{\sum_j \exp(z_{i, j} / T)} \right)$$

Optimization converged at $T = 1.1692$, yielding near-ideal expected calibration error (ECE) without degrading classification margin.


Installation

Python

pip install von-sdk
# or with uv
uv add von-sdk

# or directly from GitHub:
pip install git+https://github.com/wfzyx/von.git

TypeScript / JavaScript (Node.js & Bun)

bun add von-sdk
# or npm install von-sdk

Python API Usage

1. Discrete Decision (von.decide)

import von

result = von.decide(
    state="Database replication lag on cluster us-west-2 exceeded 45 seconds.",
    choices={
        "infrastructure": "Database, hardware, network, or server failures",
        "billing": "Invoices, payments, refunds, subscription queries",
        "feature_request": "Requests for new platform capabilities",
    },
    instructions="Classify the root cause domain of this incident.",
)

print(result.choice)         # 'infrastructure'
print(result.confidence)     # 0.8412
print(result.probabilities)  # {'infrastructure': 0.9021, 'billing': 0.0489, ...}

2. Probabilistic Condition Verification (von.judge)

import von

p_blocking = von.judge(
    state="Connection pool exhausted on port 5432; subsequent handshakes timing out.",
    instructions="Is this issue actively blocking customer operations?",
)

print(p_blocking)  # 0.9412
if p_blocking > 0.8:
    trigger_incident_response()

3. Continuous Scale Rating (von.rate)

import von

rating = von.rate(
    state="Memory utilization reached 98% with frequent OOM killer invocations.",
    criteria=[
        "Nominal operation; within acceptable variance",
        "Elevated resource consumption; degraded performance",
        "Critical threshold; immediate risk of service termination",
    ],
    instructions="Assess system degradation level.",
)

print(rating.score)       # 1.89 (scale 0.0 to 2.0)
print(rating.confidence)  # 0.78

4. Speculative Multi-Question Fan-Out (von.system_one)

Evaluate multiple heterogeneous questions in a single forward pass without latency multiplication:

import von

state = {
    "ticket_id": "INC-4091",
    "customer_tier": "enterprise",
    "message": "Payment gateway reports timeout on charge authorizations. Urgent.",
}

questions = {
    "intent": von.choice(
        instructions="What is the operational nature of this ticket?",
        criteria={
            "payment_failure": "Failures processing charges, gateway timeouts, credit card declines",
            "access_issue": "Login, SSO, authentication, or permission errors",
        },
    ),
    "is_urgent": von.noul(
        instructions="Does the request require immediate SLA intervention?",
    ),
    "severity": von.score(
        instructions="Rate the incident severity.",
        criteria=["Low", "Medium", "High", "Critical"],
    ),
}

resp = von.system_one(state=state, questions=questions)

print(resp.answers["intent"].choice)     # 'payment_failure'
print(resp.answers["is_urgent"].noul)    # 0.9204
print(resp.answers["severity"].score)    # 2.81

TypeScript / Node.js Usage

import { VonClient, choice, noul, score } from "von-sdk";

const client = new VonClient({ baseURL: "http://localhost:8000" });

const { answers } = await client.systemOne({
  state: { ticket: "Export button crashes settings page on Safari 17.2" },
  questions: {
    department: choice("Which team should handle this?", {
      frontend: "UI, client-side scripts, browser compatibility",
      billing: "Invoices, subscriptions, refunds",
    }),
    isUrgent: noul("Does this communicate production impact?"),
    severity: score("Rate bug impact", ["Minor", "Moderate", "Critical"]),
  },
});

console.log(answers.department.choice);     // "frontend"
console.log(answers.department.confidence); // 0.89
console.log(answers.isUrgent.noul);         // 0.12

Production Workflow Presets

Pre-packaged decision suites for high-frequency operational pipelines (von.presets):

import von
from von.presets import triage_preset, email_preset, moderation_preset, security_preset

# Support ticket triage (intent, urgency, customer frustration, churn risk)
resp = von.system_one(state=customer_payload, questions=triage_preset())

# Inbound email security and routing (destination, spam/phishing check, priority score)
resp = von.system_one(state=raw_email_body, questions=email_preset())

# Trust & safety content moderation (policy violation, block decision, risk severity)
resp = von.system_one(state=user_submitted_content, questions=moderation_preset())

# Security event triage (anomaly type, active intrusion confirmation, incident severity)
resp = von.system_one(state=audit_log_telemetry, questions=security_preset())

Composable Decision Patterns

High-level architectural patterns for agentic pipelines (von.patterns):

from von.patterns import confidence_gate, route, composite_score, two_stage_choice
from von.types import Choice

# 1. Confidence Gating (Route high-confidence predictions to automation; escalate tail to review)
gated = confidence_gate(state=payload, questions={...}, threshold=0.85)
# Output: {"automatic": {...}, "escalate": {...}}

# 2. Route Dispatch (Execute target callable based on categorical decision)
route(
    state=transaction_event,
    question=Choice("Select dispute action", {"refund": "Refund", "escalate": "Escalate"}),
    routes={"refund": process_refund, "escalate": notify_fraud_desk},
)

# 3. Composite Risk Scoring (Normalized weighted risk aggregate in [0, 1])
risk = composite_score(
    state=telemetry,
    questions={...},
    weights={"severity": 2.0, "is_threat": 3.0},
)
print(risk["score"])  # e.g. 0.9124

# 4. Two-Stage Routing (Handles high-cardinality taxonomies >25 options in sub-50ms)
taxonomy = {
    "cloud": {"aws": "Amazon Web Services", "gcp": "Google Cloud", "azure": "Microsoft Azure"},
    "database": {"postgres": "PostgreSQL", "mysql": "MySQL", "redis": "Redis"},
}
decision = two_stage_choice(state="Postgres replica lag exceeded limit", taxonomy=taxonomy)

Server Deployment (von serve)

Start the production-ready HTTP server compatible with the /v1/systemone specification:

# Launch server on port 8000
von serve --host 0.0.0.0 --port 8000

Wire Protocol Verification

curl -X POST http://localhost:8000/v1/systemone \
  -H "Content-Type: application/json" \
  -d '{
    "model": "von-1.0.0",
    "state": { "error": "Disk volume /var/log at 98% capacity." },
    "questions": {
      "requires_intervention": {
        "type": "noul",
        "instructions": "Does this disk space condition require operational intervention?"
      }
    }
  }'

Theoretical Homage

Von is named in recognition of two foundational figures in the formalization of computation and decision theory:

  1. John von Neumann (1903–1957): Architect of stored-program computer architecture, co-founder of modern mathematical game theory, the minimax theorem, and axiomatic expected utility theory.
  2. Ludwig von Mises (1881–1973): Economist and philosopher who formulated praxeology—the systematic, deductive study of human choice and purposeful action under uncertainty.

Academic References

If utilizing Von in research or enterprise systems, please cite the underlying methodologies:

@article{von2026systemone,
  title={Von: Non-Autoregressive System One Decision Modeling via Calibrated Bidirectional Representations},
  author={Panisa, Victor},
  year={2026},
  url={https://github.com/wfzyx/von}
}

@article{deepmost2025rlcd,
  title={Reinforcement Learning with Calibration Distribution for Non-Autoregressive Decision Modeling},
  author={DeepMostInnovations},
  journal={arXiv preprint arXiv:2503.23303},
  year={2025}
}

@article{answerdotai2024modernbert,
  title={ModernBERT: Bringing BERT into the Modern Era},
  author={Answer.AI and LightOn},
  year={2024},
  url={https://huggingface.co/blog/modernbert}
}

License

Apache-2.0. Open-source for academic, personal, and commercial deployment.

About

The open-source System One decision model. Sub-15ms, non-autoregressive, local drop-in alternative to TypeSafe Jev.

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