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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.

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Available Models

GLiNER2.5-Decide

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.

Clef

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.

Clef Flash

Cloudflare’s fast 9B multimodal decision model. Same interface as Clef, optimized for low latency.

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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

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Usage Example

cURL

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Listing Available Models

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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)

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Pricing

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.