System One & Parallel Constrained Decoding Benchmark

September 19, 2026 · View on GitHub

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Empirical evaluation and benchmarking suite comparing:

  1. TypeSafe Jev (jev-1.13.0): A frontier "System One" decision model via cloud API.
  2. Local Open-Source PCD: Parallel Constrained Decoding with Qwen 2.5 1.5B (4-bit) on Apple Silicon using Apple's MLX framework.
  3. Local Autoregressive Baseline: Standard token-by-token JSON generation with Qwen 2.5 1.5B.

Evaluated against 50 real-world adversarial, jailbreak, and benign prompts from the LMSYS lmsys/toxic-chat benchmark.


Benchmark Results (50 Real-World Samples)

MetricTypeSafe Jev (jev-1.13.0)Local Open-Source PCD (MLX)Local Autoregressive BaselineWhat This Demonstrates
Model TierFrontier System 1Open-Source 1.5BOpen-Source 1.5BFrontier vs. Small Model
Execution ModeCloud API (HTTPS)Local Apple SiliconLocal Apple SiliconNetwork vs. On-Device
Forward Passes1 Pass (O(1))1 Pass (O(1))~30.8 Passes30x Compute Reduction
Latency p50 (Median)356.5 ms (incl. network)227.2 ms (on-device)735.3 ms (on-device)Jev over HTTPS is 2x faster than local autoregressive
Latency Mean353.6 ms317.1 ms836.6 msParallelism slashes latency in half
Accuracy84.0%52.0%54.0%+32% accuracy jump from Jev's frontier RLCD training
Precision (Safety)90.9% (Only 1 FP!) ⭐36.0% (16 FPs)38.5% (16 FPs)Jev eliminates false alarms
Recall (Caught Attacks)58.8%52.9%58.8%Caught identical attack vectors
F1 Score0.7140.4290.46560%+ boost in balanced safety performance
Brier Score (Calibration)0.1096 (Near-perfect) ⭐0.3884 (Uncalibrated)N/A (Raw strings)RLCD delivers true probabilistic honesty
Schema Syntax Errors0.0% Guaranteed0.0% Guaranteed98.0% (1 Crash)Mathematical 0% schema error

Key Findings

  1. The Architectural Shift (Local PCD): Evaluating structured decisions in a single parallel forward pass (O(1)O(1)) using KV-cache broadcasting and sub-vocabulary logit slicing reduces forward passes by 96.8% (1 pass vs 31 passes) and speeds up on-device execution by 3.2x (227ms vs 735ms) with 94.0% decision concordance to full autoregressive generation.
  2. The Training Shift (TypeSafe RLCD): While open-source PCD proves the speed mechanism, TypeSafe's Reinforcement Learning for Calibrated Decisions (RLCD) delivers frontier quality: 84.0% accuracy, 90.9% precision (only 1 false positive out of 50 prompts), and a 0.1096 Brier score showing true probabilistic calibration.
  3. Catastrophic Schema Drift in Autoregressive Models: On Sample #23, when presented with a prompt asking for a list of human behaviors, the autoregressive LLM suffered instruction confusion and hallucinated new JSON keys ("human_behavior": [...]), crashing downstream schema parsers. Both Jev and Parallel Constrained Decoding were mathematically immune to this error.

Quick Start

1. Installation

git clone https://github.com/your-username/system-one-benchmark.git
cd system-one-benchmark

pip install -r requirements.txt

2. Configuration (For Live TypeSafe Jev)

Copy the example environment file and add your TypeSafe API key:

cp .env.example .env
# Edit .env:
# TYPESAFE_API_KEY=your_actual_key_here

Usage

Run Live Benchmark on TypeSafe Jev API

# Evaluates against the 50-sample ToxicChat benchmark dataset
python3 evaluate_jev.py --data-file data/guardrails_toxicchat_50.json

# Or test customer banking intent classification across 77 categories
python3 evaluate_jev.py --data-file data/banking77_50.json

Run Local Parallel Constrained Decoding (Apple Silicon MLX)

Runs on Apple Silicon M-series Macs using Apple's MLX framework:

# Evaluates both PCD and Autoregressive baseline side-by-side
python3 evaluate_local_pcd.py --task guardrails --data-file data/guardrails_toxicchat_50.json --samples 50

Run Three-Way Comparison Analysis

Compares live Jev results, local MLX results, and Hugging Face ground truth:

python3 compare_all_models.py

Download Additional Datasets from Hugging Face

# Stream and format samples from lmsys/toxic-chat or mteb/banking77
python3 download_hf_dataset.py --task guardrails --samples 100
python3 download_hf_dataset.py --task banking --samples 100

Repository Structure

system-one-benchmark/
├── data/
│   ├── guardrails_toxicchat_50.json   # 50 real-world LMSYS safety prompts
│   └── banking77_50.json              # 50 banking customer service intents
├── evaluate_jev.py                    # TypeSafe Jev API evaluation harness
├── local_pcd_engine.py                # Apple Silicon MLX parallel constrained engine
├── evaluate_local_pcd.py              # Local PCD vs Autoregressive benchmark runner
├── compare_all_models.py              # 3-way comparator (Jev vs PCD vs Autoregressive)
├── analyze_benchmark_results.py       # Metrics and failure case analyzer
├── download_hf_dataset.py             # Hugging Face dataset fetcher
├── sample_data.py                     # Offline fallback fixtures
├── benchmark_results.json             # Live TypeSafe Jev 50-sample results
├── local_mlx_results.json             # Local MLX Apple Silicon 50-sample results
├── three_way_comparison_results.json  # Consolidated benchmark metrics
├── requirements.txt                   # Dependencies
├── .env.example                       # Environment template
└── README.md                          # Documentation

References & Attribution


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