Decision-model landscape
System One Models & Typed Decision Engines
A System One model, or typed decision engine, answers typed questions about some input and returns probabilities instead of generated text. TypeSafe Jev named the category on September 15, 2026, and a wave of open models followed within days. This table tracks them side by side, with the facts each project publishes.
Checked against each project’s own pages on Oct 2, 2026.
How accurate are they on the same questions? See the System One benchmark
| Model | Approach | Size | License | Runs on | Jev API | Languages | Source |
|---|---|---|---|---|---|---|---|
| TypeSafe Jev by TypeSafe AI The hosted model that introduced the System One name and the choice, score and noul question types. Generally available and billed per token. | Hosted model | Undisclosed | Proprietary | TypeSafe cloud only | Reference API | Provider-dependent | TypeSafe docs |
| Liquid AI d1 by Liquid AI Liquid AI launched the hosted d1 on September 29, 2026 with a free tier (model name d1:free). On October 5 it released open weights on Hugging Face: d1-3B (text and images, built on LFM2.5-VL-3B, 32K context) and d1-omni-600M (text with images or audio). Liquid reports d1-3B at 48.57 on Decision Index 0.2.1, the best score under 10B (self-reported). | Hosted model, plus open-weight models | d1-3B (3.1B), d1-omni-600M (587M); hosted d1 undisclosed | LFM Open License v1.0 (open weights); hosted d1 proprietary | Liquid API, or your own hardware (d1-3B: 8 ms a decision on an RTX 4090, 30 ms on an Apple M5 Pro, per Liquid) | Hosted: yes, POST /decisions/v1/systemone, works with the TypeSafe SDKs; open weights: same question format through Transformers | 16 listed on the d1-3B card; d1-3B also reads images, d1-omni-600M images or audio | LiquidAI/ |
| OpenAI Decisions API by OpenAI Announced at DevDay on September 29, 2026 and in public beta since October 6: $0.10 per 1M input tokens, with no charge for output or cache. Returns probabilities and a confidence for choice and score answers; OpenAI says it answers about 10x faster than the Responses API. | Hosted model | Undisclosed (a version of GPT-6 Luna) | Proprietary | OpenAI API only | No, its own endpoint (POST /v1/decisions) with predicate, choice and score questions | Not stated; accepts text or images | OpenAI Decisions guide |
| Microsoft-Decision-1 by Microsoft Announced October 9, 2026 and available in Microsoft Foundry (Preview in the catalog) at $0.042 per 1M input tokens, the same as Jev, with output free. Microsoft reports the highest accuracy across 36 benchmarks and about 35x lower median latency than GPT-6 Sol (self-reported); Clef is not in its comparison, and Jev was added only in a later update. | Hosted model (post-trained Qwen3.5-9B) | 9B | Proprietary | Microsoft Foundry only | Jev request body (noul, choice, score) at its own Azure endpoint, /providers/microsoft/v1/systemone | Not stated; text or JSON only, up to 32,768 tokens | Microsoft launch post |
| Cloudflare Clef by Cloudflare Released October 1, 2026 with open weights on Hugging Face and hosted on Workers AI. On October 9 Cloudflare added Clef-Omni (audio input, $0.15 per 1M input tokens) and cut Clef-Flash to $0.038, below Jev, with a 24,576-token hosted context. Cloudflare reports Clef leading 7 of 10 decision benchmarks against Jev, and Clef-Flash at 38.8 ms median latency (self-reported). | Fine-tuned Qwen models with a joint decision head | 27B (Clef) / 9B (Clef-Flash) / 30B-A3B (Clef-Omni) | Apache 2.0 | Workers AI, or your own large GPU (tested on one H200) | Yes, Jev / SystemOne request and response format | Not stated; accepts text, JSON, images and video, and Clef-Omni also audio | Cloudflare/ |
| Laya by Convai Innovations Non-autoregressive choice, score and noul heads on ModernBERT and mmBERT encoders, with a Router, fine-tuning and many community runtimes. | Trained encoder with decision heads | 322M / 421M | Apache 2.0 | CPU, CUDA, Apple Silicon | Yes, through laya-serve | English, plus a 100+ language checkpoint | NandhaKishorM/ |
| Kev by Jared Palmer Small Jev-like models on Qwen3.5 and Qwen3.8 bases. Each checkpoint ships a fitted temperature, and a fine-tune and deploy loop runs on Modal. | Fine-tuned Qwen models | 0.8B / 4B / 9B / 27B | Apache 2.0 | Apple Silicon Mac (0.8B) up to one 80 GB GPU (27B) | Yes, the TypeSafe SDK works unchanged | Not stated | jaredpalmer/ |
| OpenDecider by Manjunath Shiva Distilled from two open teacher models. The 400M nano model scores 0.796 on the typed-decisions benchmark, against 0.766 for Laya's fine-tuned checkpoint and 0.754 for Jev (author's measurements). Early release, updated often. | Trained encoder (nano); fine-tuned Qwen (small, medium) | ~400M / 4B / 30B MoE | Apache 2.0 | CPU, CUDA, Apple Silicon (MLX builds); 30B needs several NVIDIA GPUs | Yes, `opendecider serve` (0.2.0+): POST /v1/systemone and /batch | English (only English evaluated so far) | manjunathshiva/ |
| Decider by Mapika One-pass typed decisions with calibrated probabilities, trained on public data and labels from a local Qwen3.5-27B teacher. Choice supports 2 to 255 options. | Fine-tuned Qwen models | 2B / 4B / 35B MoE | Apache 2.0 | Local GPU, vLLM serving | Yes, a /v1/systemone endpoint | Not stated | Mapika/ |
| Von by wfzyx Built on ModernBERT-Large. Version 1.2 scores each option independently, so the answer no longer depends on the order the options are listed in. | Trained encoder, non-autoregressive | 395M | Apache 2.0 | Local CPU or GPU | Yes, a /v1/systemone server | English | wfzyx/ |
| Bespoke Nimble by Bespoke Labs Publishes the data curation, training and serving recipe behind Bespoke-Nimble-9B, which now takes 8,192-token inputs and up to 255 choices per field. | Fine-tuned model with training recipe | 9B | Not stated in the repository | Apple Silicon, NVIDIA GPU | No, its own schema format | Not stated | bespokelabsai/ |
| SemIf (formerly OpenJev) by TheoLeeCJ Scores typed options directly from a frozen open model with no answer text or JSON parsing, with per-workload temperature calibration. | Training-free, reads option probabilities from open LLMs | Depends on the model (2B to 27B tested) | MIT | RTX 3090, Apple Silicon, browser (WebGPU demo) | Reproduces the interface pattern | Depends on the model | TheoLeeCJ/ |
| Rizzo Flow by Rizzo AI Academy A local take on Jev with a LoRA fine-tune of Spark-X2.5. The project reports 0.648 on typed-decisions against 0.727 for Jev, and notes that probabilities are uncalibrated unless you calibrate them on your own data. | Fine-tuned LLM (Spark-X2.5) on llama.cpp | 1.7B / 4B | Apache 2.0 | llama.cpp: CUDA, Metal, Vulkan, ROCm, SYCL or CPU | Yes, POST /v1/systemone | Not stated | Rizzo-AI-Academy/ |
| AnyJev by Nokia Applied Research Turns an existing LLM into a Jev-style decision model by reading its hidden states, with debiasing and calibration levels and no task-specific training. | Training-free library over existing LLMs | Depends on the model | Apache 2.0 | Hugging Face models, vLLM serving | Serves its own decision endpoint | Depends on the model | nokia-applied-research/ |
| NanoJev by TianyuCodings A compact replica with an end-to-end training pipeline, evaluated on game tasks such as ViZDoom, a maze and Snake against Jev. | Small parallel decision model | 0.6B | MIT | Local GPU | Not stated | Not stated | TianyuCodings/ |
| Tev1-4B-experimental by Together AI An experimental supervised fine-tune of Qwen3.5-4B released on September 23, 2026, with the data recipe and a guide to training a similar classifier. | Fine-tuned LLM, answers with one option letter | 4B | Weights license being finalized; code MIT | Together API, or self-hosted Transformers and GGUF | No, chat completions with 2 to 24 options | Not stated | togethercomputer/ |
| GLiNER2.5-Decide by Fastino Takes label sets at call time and scores several heads in one pass. Built for operational decisions such as intent, routing, sentiment and priority. | Encoder classifier | 340M (also 1B, and 287M multilingual) | Apache 2.0 | CPU or GPU with the gliner2 package | No, its own classify_text API | English, plus a multilingual variant | fastino/ |
| OpenThai-SystemOne by iApp Technology A Qwen3.5-0.8B text tower whose output head is replaced by a 256-way slot softmax, continued-pretrained on Thai. | Fine-tuned model with a slot head | 0.8B | Apache 2.0 | CUDA, MPS, CPU | Yes, mirrors POST /v1/systemone | Thai, English | iapp-technology/ |
| djev (DiffusionGemma-Jev) by mmastrac Reads Jev-style decisions from DiffusionGemma, a discrete diffusion model, in one denoise step through vLLM. The djev-dev fork adds native image inputs and live camera sampling. | Training-free, reads decisions from a diffusion LLM | DiffusionGemma (26B-A4B in the DGX Spark recipe) | Apache 2.0 | NVIDIA GPU with vLLM | Yes, POST /v1/systemone | Not stated | mmastrac/ |
| Jev-Omni by akhilaaa3 A decision classifier for text, images, audio and video, fine-tuned on 30,000 questions: a probability per option instead of an explanation. Reports 86.15% on matched JevBench groups (self-reported). | Fine-tuned multimodal model | 12B (Gemma 4 12B) | Apache 2.0 | NVIDIA GPU | Not stated | Not stated | akhilaaa3/ |
| Open-Jev by Zefan Cai Scores the candidates you supply for choice, noul and score questions without generating an answer, using a trained head on top of Qwen3.5. | LoRA adapter + scalar decision head | 2B, 9B, 27B (Qwen3.5) | Apache 2.0 | NVIDIA GPU | Yes, a local /v1/systemone server | Not stated | Zefan-Cai/ |
| JevK5 by alibiserikbay Qwen3.5-4B with a merged LoRA, read out with the SemIf protocol and one calibration temperature. Questions with more than 16 options are read in several passes. | Fine-tuned LLM with calibrated letter readout | 4B (Qwen3.5-4B) | Apache 2.0 | Local GPU | Yes, TypeSafe-style /v1/systemone runtime | English | allebee/ |
| open-jev-deberta-v3-large by kotoba-lang An independent reproduction of the Jev interface: choice (up to 255 options), score (2 to 10 levels) and noul in one forward pass, measured on public gold labels. | Trained encoder, non-autoregressive | 434M (DeBERTa-v3-large) | Apache 2.0 | Local CPU or GPU | No, a Python library | English | com-kotobalabs/ |
| AgentJev by malevrigns The language-model head is removed and a candidate head scores the options. The published checkpoint judges whether a coding task is actually finished. | LLM backbone + order-invariant candidate head | 0.6B (Qwen3-0.6B) | Apache 2.0 | Local CPU or GPU | No, its own server and client | English, Chinese | malevrigns/ |
| Jev-Style by chaoliangUNSW GGUF decision models that return calibrated option probabilities from a single token. v3 reports 79.2% on 2,000 typed decisions and takes 25,600-token inputs. | Fine-tuned LLM, one-token decision (GGUF) | 0.8B (v3); 2B (v1) | Apache 2.0 | llama.cpp, LM Studio (CPU or GPU) | No, chat completions with logprobs | 51 (v3) | jevstyle.com |
| Anarkali by ToufiqQureshi A 68M encoder that beats Jev on the public typed-decisions benchmark (74.0% vs 72.7%) and comes within 2.6 points of Laya at a sixth of the size, with the lowest calibration error of the three (author-reported). | Trained encoder (Ettin), non-autoregressive | 68M | Apache 2.0 | CPU or GPU via a single 273 MB ONNX file | Yes, POST /v1/systemone | English only | ToufiqQureshi/ |
| Jeeves by PostHog Thinks before it answers: 0.935 on the public JevBench items vs 0.866 for Jev (0.865 vs 0.730 on the hard tier), at about 0.3 s per request without thinking and a 3.3 s median with it on one H100. Jev still leads on MMLU-Pro (author-reported). | Fine-tuned LLM (LoRA + pointer head) that reasons before deciding | 9B (Qwen3.5-9B) | MIT code, Apache 2.0 weights | CUDA GPU (FP8 kernel needs Hopper) | Yes, a local /v1/systemone server | Not stated | PostHog/ |
| OpenJev-4B by ejhshen (Junhao Shen) Options and criteria are inputs, so the output follows whatever candidates a request supplies, and reordering them does not change the answer. Trained with SFT then RL on the public OpenJevData-140k set; training code included. | LLM backbone + option-set decision head, non-autoregressive | 4B (Qwen3.5-4B) | MIT | CUDA GPU | Yes, a local /v1/systemone server | Not stated | ejhshen/ |
Which one fits your situation?
You already call Jev and want to self-host
Start with a model that serves POST /v1/systemone: Laya (laya-serve), Kev, Decider, OpenDecider, Von or OpenThai-SystemOne. Existing client code points at the new base URL.
CPU-only servers or low latency
Encoder models are the smallest here: Laya (322M to 421M), Von (395M) and GLiNER2.5-Decide (340M).
Highest accuracy on a large GPU
The larger fine-tuned LLMs, such as Kev-9B or Kev-27B, Decider 35B MoE and Bespoke Nimble 9B, or Jeeves 9B if a few seconds of reasoning per request is acceptable. Measure on your own data before switching.
Non-English input
laya-multilingual covers 100+ languages; OpenThai-SystemOne targets Thai and English; GLiNER2.5-multi-Decide is Fastino’s multilingual variant.
A hosted API other than Jev
Liquid AI d1 speaks the same System One API and has a free tier; switch by changing the base URL and model name. Cloudflare Workers AI serves Clef and Clef-Flash with the same request body but its own URL and API token, and you can also run their weights yourself. Microsoft-Decision-1 on Microsoft Foundry takes the same request body at its own Azure endpoint, for the same price as Jev ($0.042 per 1M input tokens). The OpenAI Decisions API is open to all developers in public beta ($0.10 per 1M input tokens), but uses its own request format.
No training at all
Training-free approaches such as AnyJev and SemIf read decisions from an open LLM you already run.
Replacing Jev?
See which open models and servers accept Jev requests unchanged, and what switching involves.
Compare Jev alternativesWhat makes a System One model different?
A System One model reads a state, such as a ticket, an email or some JSON, plus a set of typed questions. It returns an answer and a probability for every allowed option in a single pass, with no free-form text to generate or parse.
The projects above get there in different ways. Some train an encoder with decision heads (Laya, Von), some fine-tune an open LLM (Kev, Decider, Nimble, Tev1, Rizzo Flow), and some read decisions out of an existing LLM without training (AnyJev, SemIf). That changes the model size, the hardware you need, and how the probabilities are calibrated.
Benchmarks in this space are young and mostly self-reported, on different datasets. Compare deployment, calibration, language coverage, option count and latency, and test on your own labelled data before choosing.