> ## Documentation Index
> Fetch the complete documentation index at: https://docs.matterai.so/llms.txt
> Use this file to discover all available pages before exploring further.

# System One: Decision Models

> Structured decision models for fast, deterministic classification — intent, routing, sentiment, priority, and policy decisions.

System One provides structured decision models that evaluate a set of typed questions over a piece of text and return deterministic answers in a single pass. Unlike chat models, these models do not reason, explain, or generate free-form text — they are built for fast, reliable classification tasks like intent detection, routing, sentiment analysis, priority scoring, and policy decisions.

## Available Models

<CardGroup cols={1}>
  <Card title="GLiNER2.5-Decide" icon="brain-circuit">
    Fastino's 340M-parameter open-weight encoder decision model. Evaluates typed
    questions (choice, score, yes/no) over text in a single pass with no prompt
    templates or token generation. Free to use.
  </Card>

  <Card title="Clef" icon="microchip">
    Cloudflare's 27B multimodal decision model. Reads the state as text, JSON,
    images, or video and returns a probability for every allowed option of every
    question.
  </Card>

  <Card title="Clef Flash" icon="bolt">
    Cloudflare's fast 9B multimodal decision model. Same interface as Clef,
    optimized for low latency.
  </Card>
</CardGroup>

## How It Works

Instead of a chat message, you send a **state** (the text to evaluate) and a **schema of typed questions**. The model jointly decodes a structured answer for every question in a single pass — no prompt templates, no token generation.

Supported question types:

* **choice** — pick one option from a set of criteria
* **score** — rate the state on an ordered scale
* **noul** — yes/no (null or non-null) decision

## Usage Example

```bash cURL theme={null}
curl -X POST https://api.matterai.so/v1/system \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $MATTERAI_API_KEY" \
  -d '{
    "model": "fastino/gliner2.5-decide",
    "state": "The customer said the delivery was late but the product quality was excellent.",
    "questions": {
      "sentiment": {
        "type": "choice",
        "instructions": "What is the overall sentiment of this feedback?",
        "criteria": {
          "positive": "Customer is happy overall",
          "negative": "Customer is unhappy overall",
          "mixed": "Customer has both good and bad things to say"
        }
      },
      "satisfaction": {
        "type": "score",
        "instructions": "Rate overall customer satisfaction from low to high.",
        "criteria": ["low", "medium", "high"]
      },
      "needs_followup": {
        "type": "noul",
        "instructions": "Does this feedback require a follow-up from the support team?"
      }
    }
  }'
```

## Listing Available Models

```bash theme={null}
curl https://api.matterai.so/v1/system/models
```

## Constraints

* `state` must be a non-empty string, up to 100,000 characters
* `questions` must contain 1 to 100 entries, each with a `type`
* Clef and Clef Flash accept an optional `images` array of up to 4 entries
* System One is only available with a MatterAI API key (not JWT sessions)

## Pricing

| Model | Price |
| - | - |
| GLiNER2.5-Decide | Free |
| Clef | \$0.24 per 1M input tokens |
| Clef Flash | \$0.09 per 1M input tokens |

<Note>
  System One models are separate from the chat model catalog. They do not
  appear in agent model pickers and are only reachable through the `/v1/system`
  endpoint.
</Note>


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