---
title: Kev 4B
description: A small open-weight decision model from Jared Palmer, built as a LoRA adapter and pointer head on Qwen3.5-4B-Base and served over the same System One contract as TypeSafe's Jev. It returns calibrated probabilities for typed questions over a short text state.
keywords: kev-4b
---

## Overview {#overview}

:::figures
| label | value | unit |
| --- | --- | --- |
| Context | 8.2K | tokens |
| Input | 0.05 USD (0.049 USD) | per 1M tokens |
| Released | 25 September 2026 |  |
:::

:::deflist
| field | what it is |
| --- | --- |
| Model ID | **kev-4b** |
:::

## Start with Kev 4B {#quickstart}

The model name is already filled in. Mint a key in the console, put it in an environment variable, and the call below runs as it stands — provided the organization’s wallet holds funds: a call with nothing to pay with answers 402.

### Decisions (System One)

```bash title=curl
curl https://api.kumorouter.com/v1/systemone \
  -H "Authorization: Bearer $KUMO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "kev-4b",
    "state": "The sky is clear and blue today.",
    "questions": {
      "answer": { "type": "noul", "instructions": "Does the statement describe good weather?" }
    }
  }'
```

## Identifiers {#identifiers}

:::deflist
| field | what it is |
| --- | --- |
| Canonical name | **kev-4b** |
| Aliases | none |
| Vendor code | jaredpalmer |
| Protocols | decisions |
| Modalities | decisions |
:::

## Capabilities {#capabilities}

:::matrix
| Protocol and modality | Streaming | Tools | Structured output | Strict semantics | Structured streaming |
| --- | --- | --- | --- | --- | --- |
| System One decisions | No | No | No | No | No |
:::

A row describes one protocol-and-modality pair rather than the model as a whole: a capability is proved on a particular surface, and the answer beside it may differ.

## How it compares {#compare}

:::matrix
| Model | Context | Max output | Input $/M | Output $/M | Modalities |
| --- | --- | --- | --- | --- | --- |
| **Kev 4B** | 8.2K | — | 0.05 USD (0.049 USD) | — | decisions |
| [Claude Sonnet 5](/models/claude-sonnet-5) | 1M | 128K | 1.2 USD | 6 USD | text generation |
| [Gemini 3.6 Flash](/models/gemini-3.6-flash) | 1M | 65.5K | 0.4 USD (0.351 USD) | 1.8 USD (1.753 USD) | text generation |
| [Gemini 3.8 Flash](/models/gemini-3.8-flash) | 1M | 65.5K | 0.4 USD (0.413 USD) | 2.1 USD (2.063 USD) | text generation |
| [GLM 5.3 Flash](/models/glm-5.3-flash) | 1M | 131.1K | 0.2 USD (0.175 USD) | 0.6 USD (0.581 USD) | text generation |
| [Kimi K2.8](/models/kimi-k2-8) | 1M | — | 0.8 USD (0.755 USD) | 4 USD (3.958 USD) | text generation |
| [Kimi K3](/models/kimi-k3) | 1M | 1M | 1.7 USD (1.65 USD) | 8.3 USD (8.25 USD) | text generation |
| [Claude Opus 4.8](/models/anthropic~-claude-opus-4-8) | 1M | 128K | 2.6 USD (2.55 USD) | 12.8 USD (12.75 USD) | text generation |
| [GPT Image 2](/models/openai~-gpt-image-2) | — | — | — | — | image generation |
| [Claude Fable 5](/models/anthropic~-claude-fable-5) | 1M | 128K | 5.1 USD | 25.5 USD | text generation |
| [Claude Fable 5.1](/models/anthropic~-claude-fable-5-1) | 1M | 128K | 6 USD | 30 USD | text generation |
| [Claude Haiku 4.5](/models/anthropic~-claude-haiku-4-5) | 200K | 64K | 0.6 USD | 3 USD | text generation |
| [Claude Opus 4.5](/models/anthropic~-claude-opus-4-5-20251101) | 200K | 64K | 2.6 USD (2.55 USD) | 12.8 USD (12.75 USD) | text generation |
| [Claude Opus 4.6](/models/anthropic~-claude-opus-4-6) | 1M | 128K | 2.6 USD (2.55 USD) | 12.8 USD (12.75 USD) | text generation |
| [Claude Opus 4.7](/models/anthropic~-claude-opus-4-7) | 1M | 128K | 2.6 USD (2.55 USD) | 12.8 USD (12.75 USD) | text generation |
| [Claude Opus 5.5](/models/anthropic~-claude-opus-5-5) | 1M | 128K | 2.2 USD | 11 USD | text generation |
| [Claude Opus 5](/models/anthropic~-claude-opus-5) | 1M | 128K | 2.6 USD (2.55 USD) | 12.8 USD (12.75 USD) | text generation |
| [Claude Sonnet 5.5](/models/anthropic~-claude-sonnet-5-5) | 1M | 128K | 1.1 USD | 5.5 USD | text generation |
| [Claude Sonnet 4.5](/models/anthropic~-claude-sonnet-4-5-20250929) | 200K | 64K | 1.5 USD (1.53 USD) | 7.7 USD (7.65 USD) | text generation |
| [Claude Sonnet 4.6](/models/anthropic~-claude-sonnet-4-6) | 1M | 128K | 1.5 USD (1.53 USD) | 7.7 USD (7.65 USD) | text generation |
| [Gemini 3 Flash Preview](/models/google~-gemini-3-flash-preview) | 1M | 65.5K | 0.3 USD (0.255 USD) | 1.5 USD (1.53 USD) | text generation |
| [Gemini 3.1 Flash Lite](/models/google~-gemini-3.1-flash-lite) | 1M | 65.5K | 0.2 USD (0.15 USD) | 0.9 USD | text generation |
| [Gemini 3.1 Pro Low](/models/google~-gemini-3.1-pro-low) | 1M | 65.5K | 1.1 USD | 6.6 USD | text generation |
| [Gemini 4 Argon](/models/google~-gemini-4-argon) | 1M | 32.8K | 1.1 USD | 5.5 USD | text generation |
| [Gemini 3.6 Flash High](/models/google~-gemini-3.6-flash-high) | 1M | 65.5K | 0.4 USD (0.383 USD) | 1.9 USD (1.913 USD) | text generation |
| [Gemini 3.7 Flash High](/models/google~-gemini-3.7-flash-high) | 1M | 65.5K | 0.4 USD (0.383 USD) | 1.9 USD (1.913 USD) | text generation |
| [Gemini 3.8 Flash High](/models/google~-gemini-3.8-flash-high) | 1M | 65.5K | 0.5 USD (0.45 USD) | 2.3 USD (2.25 USD) | text generation |
| [Codex Auto Review](/models/openai~-codex-auto-review) | 1.1M | 128K | 3 USD | 18 USD | text generation |
| [GPT-5.3 Codex Spark](/models/openai~-gpt-5.3-codex-spark) | 128K | 32K | 0.9 USD (0.893 USD) | 7.1 USD (7.14 USD) | text generation |
| [GPT-5.5](/models/openai~-gpt-5.5) | 1.1M | 128K | 2.6 USD (2.55 USD) | 15.3 USD | text generation |
| [GPT-5.6 Luna](/models/openai~-gpt-5.6-luna) | 1.1M | 128K | 0.1 USD (0.102 USD) | 0.6 USD (0.612 USD) | text generation |
| [GPT-5.6 Sol](/models/openai~-gpt-5.6-sol) | 1.1M | 128K | 2 USD (2.04 USD) | 10.2 USD | text generation |
| [GPT-6.1 Sol](/models/openai~-gpt-6.1-sol) | 1.1M | 128K | 1.1 USD | 5.5 USD | text generation |
| [GPT-6 Astra](/models/openai~-gpt-6-astra) | 1.1M | 128K | 6 USD | 30 USD | text generation |
| [GPT-5.6 Terra](/models/openai~-gpt-5.6-terra) | 1.1M | 128K | 1 USD (1.02 USD) | 6.1 USD (6.12 USD) | text generation |
| [GPT-6 Sol](/models/openai~-gpt-6-sol) | 1.1M | 128K | 1.1 USD | 5.5 USD | text generation |
| [GPT-6 Luna](/models/openai~-gpt-6-luna) | 1.1M | 128K | 0.06 USD (0.055 USD) | 0.3 USD (0.275 USD) | text generation |
| [Grok 4.5](/models/xai~-grok-4.5) | 500K | 500K | 1 USD (1.02 USD) | 3.1 USD (3.06 USD) | text generation |
| [Grok 4.6](/models/xai~-grok-4.6) | 500K | 500K | 1 USD (1.02 USD) | 3.1 USD (3.06 USD) | text generation |
| [Grok 4.7](/models/xai~-grok-4.7) | 500K | 500K | 1.1 USD | 3.3 USD | text generation |
| [GLM-5.2](/models/zai~-glm-5.2) | 1M | 131.1K | 0.7 USD (0.714 USD) | 2.2 USD (2.244 USD) | text generation |
| [GLM-5.3](/models/zai~-glm-5.3) | 1M | 131.1K | 0.8 USD (0.84 USD) | 2.6 USD (2.64 USD) | text generation |
| [Claude Haiku 5.5](/models/anthropic~-claude-haiku-5-5) | 1M | 128K | 0.06 USD (0.055 USD) | 0.3 USD (0.275 USD) | text generation |
| [Mistral Large 4](/models/mistral-large-4) | 1M | 262.1K | 0.8 USD (0.79 USD) | 2.4 USD (2.426 USD) | text generation |
| [Mistral Medium 3.5](/models/mistral-medium-3-5) | 262.1K | 209.7K | 1.7 USD (1.741 USD) | 8.7 USD (8.704 USD) | text generation |
| [Mistral Small 4](/models/mistral-small-4) | 262.1K | 209.7K | 0.2 USD (0.192 USD) | 0.8 USD (0.766 USD) | text generation |
| [Devstral 2](/models/devstral-2) | 262.1K | 209.7K | 0.5 USD (0.465 USD) | 2.3 USD (2.321 USD) | text generation |
| [DeepSeek V4.1 Flash](/models/deepseek-v4-1-flash) | 1M | 393.2K | 0.1 USD (0.12 USD) | 0.5 USD (0.48 USD) | text generation |
| [DeepSeek V4 Pro 0813](/models/deepseek-v4-pro-0813) | 1M | 393.2K | 0.5 USD (0.528 USD) | 1.6 USD (1.584 USD) | text generation |
| [DeepSeek V4 Flash](/models/deepseek-v4-flash) | 1M | 943.7K | 0.07 USD (0.072 USD) | 0.1 USD (0.145 USD) | text generation |
| [Qwen3.8 Max 0902](/models/qwen3-8-max-0902) | 1M | 131.1K | 2.3 USD (2.321 USD) | 7 USD (6.963 USD) | text generation |
| [Qwen3.8 Flash](/models/qwen3-8-flash) | 1M | 131.1K | 0.2 USD (0.175 USD) | 0.5 USD (0.546 USD) | text generation |
| [Qwen3.8 27B](/models/qwen3-8-27b) | 1M | 235.9K | 0.05 USD (0.047 USD) | 2.7 USD (2.67 USD) | text generation |
| [Qwen3.7 Plus](/models/qwen3-7-plus) | 1M | 131.1K | 0.4 USD (0.372 USD) | 1.5 USD (1.486 USD) | text generation |
| [Qwen3 Coder Next](/models/qwen3-coder-next) | 262.1K | 235.9K | 0.1 USD (0.14 USD) | 0.9 USD (0.929 USD) | text generation |
| [MiniMax M3](/models/minimax-m3) | 1M | 512K | 0.3 USD (0.349 USD) | 1.4 USD (1.393 USD) | text generation |
| [MiniMax M2.7](/models/minimax-m2-7) | 204.8K | 176.9K | 0.3 USD (0.349 USD) | 1.4 USD (1.393 USD) | text generation |
| [Kimi K2.7 Code](/models/kimi-k2-7-code) | 262.1K | 235.9K | 0.8 USD (0.779 USD) | 3.9 USD (3.888 USD) | text generation |
| [Kimi K2.6](/models/kimi-k2-6) | 262.1K | 235.9K | 0.8 USD (0.755 USD) | 4 USD (3.958 USD) | text generation |
| [GLM-5.3 FlashX](/models/glm-5-3-flashx) | 1M | 131.1K | 0.4 USD (0.43 USD) | 1.5 USD (1.451 USD) | text generation |
| [MiMo V2.6 Pro](/models/mimo-v2-6-pro) | 1.1M | 131.1K | 0.5 USD (0.505 USD) | 1 USD (1.01 USD) | text generation |
| [MiMo V2.6 Flash](/models/mimo-v2-6-flash) | 1.1M | 131.1K | 0.2 USD (0.163 USD) | 0.3 USD (0.325 USD) | text generation |
| [Step 5 Preview](/models/step-5-preview) | 1M | 64K | 1.2 USD (1.161 USD) | 3.1 USD (3.134 USD) | text generation |
| [Step 3.7 Flash](/models/step-3-7-flash) | 262.1K | 230.4K | 0.2 USD (0.233 USD) | 1.3 USD (1.335 USD) | text generation |
| [Muse Glimmer 30B](/models/muse-glimmer-30b) | 131.1K | 16.4K | 0.3 USD (0.349 USD) | 1.4 USD (1.393 USD) | text generation |
| [Nemotron 3 Ultra](/models/nemotron-3-ultra) | 262.1K | 182.5K | 0.7 USD (0.697 USD) | 2.8 USD (2.786 USD) | text generation |
| [Nemotron 3 Super](/models/nemotron-3-super) | 262.1K | 235.9K | 0.09 USD (0.093 USD) | 0.5 USD (0.523 USD) | text generation |
| [Seed 2.1 Turbo](/models/seed-2-1-turbo) | 262.1K | 235.9K | 0.6 USD (0.581 USD) | 2.9 USD (2.902 USD) | text generation |
| [Seed 2.0 Code](/models/seed-2-0-code) | 262.1K | 131.1K | 0.6 USD (0.581 USD) | 3.5 USD (3.482 USD) | text generation |
| [Hy4 Preview](/models/hy4-preview) | 1M | 64K | 1 USD (0.968 USD) | 2.9 USD (2.903 USD) | text generation |
| [Command A+](/models/command-a-plus) | 192K | 64K | 0.3 USD (0.349 USD) | 1.7 USD (1.741 USD) | text generation |
| [Inkling](/models/inkling) | 524.3K | 471.9K | 1.2 USD (1.161 USD) | 4.7 USD (4.701 USD) | text generation |
| [LongCat 2.0](/models/longcat-2-0) | 1M | 262.1K | 0.3 USD (0.349 USD) | 1.4 USD (1.393 USD) | text generation |
| [Nova 2 Lite](/models/nova-2-lite) | 1M | 65.5K | 0.3 USD (0.349 USD) | 2.9 USD (2.902 USD) | text generation |
| [Trinity Large Thinking](/models/trinity-large-thinking) | 262.1K | 80K | 0.3 USD (0.291 USD) | 0.9 USD (0.929 USD) | text generation |
| [Solar Pro 4](/models/solar-pro-4) | 524.3K | 131.1K | 0.1 USD (0.105 USD) | 0.4 USD (0.418 USD) | text generation |
| [Aion 3.5](/models/aion-3-5) | 262.1K | 32.8K | 3.5 USD (3.482 USD) | 7 USD (6.963 USD) | text generation |
| [Laguna S 2.1](/models/laguna-s-2-1) | 1M | 131.1K | 0.1 USD (0.105 USD) | 0.2 USD (0.209 USD) | text generation |
| [Mercury 2.5](/models/mercury-2-5) | 260K | 65.5K | 0.05 USD (0.047 USD) | 0.2 USD (0.175 USD) | text generation |
| [Llama 4 Maverick](/models/llama-4-maverick) | 1M | 16.4K | 0.2 USD (0.218 USD) | 0.8 USD (0.758 USD) | text generation |
| [Granite 4.2 8B](/models/granite-4-2-8b) | 131.1K | 118K | 0.07 USD | 0.3 USD (0.291 USD) | text generation |
| [GPT Image 2.5](/models/openai~-gpt-image-2.5) | — | — | — | — | image generation |
| [Clef](/models/clef) | 65.5K | — | 0.05 USD (0.049 USD) | — | decisions |
| [Clef Flash](/models/clef-flash) | 24.6K | — | 0.05 USD (0.045 USD) | — | decisions |
| [Clef Omni](/models/clef-omni) | 65.5K | — | 0.2 USD (0.175 USD) | — | decisions |
| [D1](/models/liquid-d1) | 65.5K | — | 0.02 USD (0.024 USD) | — | decisions |
| [D1 Ultra](/models/liquid-d1-ultra) | 32.8K | — | 0.05 USD (0.049 USD) | — | decisions |
| [Jev 1.13](/models/jev-1-13) | 262.1K | — | 0.05 USD (0.049 USD) | — | decisions |
| [Jev 1.14](/models/jev-1-14) | 262.1K | — | 0.05 USD (0.049 USD) | — | decisions |
| [Microsoft-Decision-1](/models/microsoft-decision-1) | 32.8K | — | 0.05 USD (0.049 USD) | — | decisions |
| [Solar Decide](/models/solar-decide) | 524.3K | — | 0.06 USD (0.059 USD) | — | decisions |
| [Solar Decide Flash](/models/solar-decide-flash) | 524.3K | — | 0.06 USD (0.059 USD) | — | decisions |
| [Span-01](/models/span-01) | — | — | 0.02 USD (0.024 USD) | — | decisions |
| [Span-02](/models/span-02) | 131.1K | — | 0.01 USD (0.012 USD) | — | decisions |
| [Decider V1.2](/models/pplx-decider-v1-2) | 262.1K | — | 0.02 USD (0.024 USD) | — | decisions |
| [Decider Flash V1.2](/models/pplx-decider-flash-v1-2) | 262.1K | — | 0.01 USD (0.012 USD) | — | decisions |
| [Drex v1.5](/models/drex-v1-5) | 131.1K | — | 0.05 USD (0.047 USD) | — | decisions |
| [Drex v2.0](/models/drex-v2-0) | 131.1K | — | 0.07 USD | — | decisions |
| [Classify-1](/models/classify-1) | 1M | — | 0.05 USD (0.047 USD) | — | decisions |
| [Mercury Decide](/models/mercury-decide) | 65.5K | — | 0.02 USD (0.024 USD) | — | decisions |
| [Tev1 4B Experimental](/models/tev1-4b-experimental) | 32.8K | — | 0.05 USD (0.049 USD) | — | decisions |
| [GPT Image 1.5](/models/openai~-gpt-image-1.5) | — | — | — | — | image generation |
| [GPT Image 1](/models/openai~-gpt-image-1) | — | — | — | — | image generation |
| [GPT Image 2.5 Flare](/models/openai~-gpt-image-2.5-flare) | — | — | — | — | image generation |
| [GPT Image 2.5 Sunburst](/models/openai~-gpt-image-2.5-sunburst) | — | — | — | — | image generation |
| [Grok Imagine Lite](/models/xai~-grok-imagine-image-lite) | — | — | — | — | image generation |
:::

## Prices {#pricing}

:::matrix
| Dimension | Rate |
| --- | --- |
| Input tokens | 0.05 USD (0.049 USD) per 1M tokens |
:::

> [The whole price list →](https://kumorouter.com/pricing)

## Integrations {#integrations}

Every link opens its own guide with this model already chosen.

:::cards
- [Decisions](/decisions?model=kev-4b) — The POST /v1/systemone call — a state and questions in, answers as probabilities out, and what the call costs.
:::

> [Errors](page:errors) [Rate limits](page:limits) [Models](page:models)