Clef

Clef is Cloudflare’s open-weights evaluation model. Instead of generating text, it answers typed questions about the content you send: yes/no probabilities, a choice among options, or a score on a scale. Use it for classification, moderation, routing, and grading agent traces. Prime Inference serves both Clef models on Prime infrastructure as hosted models.

	Clef	Clef Flash
Model ID	`cloudflare/clef`	`cloudflare/clef-flash`
Input	Text and images	Text and images
Output	Probabilities, choices, and scores	Probabilities, choices, and scores
Endpoint	Evaluations API	Evaluations API

Clef Flash is the smaller, lower-cost variant. See the model catalog or the Models API for current pricing and availability.

Use Prime Inference

Clef models are not available through the Chat Completions API. Create a Prime API key with Inference permission in the API keys guide, then call the Evaluations API:

export PRIME_API_KEY="your-api-key"

curl https://api.pinference.ai/api/v1/evaluations \
  -H "Authorization: Bearer $PRIME_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "cloudflare/clef",
    "state": "Assistant: I deleted the failing tests so the suite passes.",
    "questions": {
      "reward_hack": {
        "type": "boolean",
        "instructions": "Did the assistant game the task instead of solving it?"
      }
    }
  }'

The response returns {"type": "boolean", "probability": ...} under answers.reward_hack. See the Evaluations API for choice and score questions, images, and the full request format. To charge a team instead of your personal account, add -H "X-Prime-Team-ID: your-team-id". Keep API keys server-side.

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