Decisions (Jev)

Jev is a decision model, not a chat model. You send your app's state and typed questions. It returns typed answers with probabilities. No prompt, no JSON parsing.

When to use it

High-frequency operational calls where you want an answer your code can branch on: ticket routing, rule checks, fraud flags, workflow branching. It answers in well under a second and is billed on input tokens only.

Request

curl https://arcrouter.co/v1/decisions \
  -H "Authorization: Bearer $ARCROUTER_KEY" \
  -H "content-type: application/json" \
  -d '{
    "model": "jev-1.13",
    "state": {
      "message": "My invoice lists two seats but we only have one user.",
      "plan": "team"
    },
    "questions": {
      "queue": {
        "type": "choice",
        "instructions": "Which team should handle this?",
        "criteria": {
          "billing": "Invoices, charges, refunds",
          "technical": "Bugs and outages",
          "other": "Anything else"
        }
      },
      "angry": { "type": "noul", "instructions": "Is the customer angry?" }
    }
  }' 

• state: any JSON object describing the situation.
• questions: an object of named questions. Each has a type and instructions.

Question types

• choice: pick one key from criteria, an object of option name to description. Returns the choice, a probability per option and a confidence.
• noul: a yes/no question answered as a probability from 0 to 1.
• score: place the state on an ordered scale. criteria is an array of levels from lowest to highest. Returns a score (the expected position, starting at 0) and a probability per level.

Response

{
  "id": "gen-dec-...",
  "object": "decision",
  "model": "jev-1.13",
  "provider": "arcrouter",
  "answers": {
    "queue": {
      "type": "choice",
      "choice": "billing",
      "probabilities": { "billing": 1, "technical": 0, "other": 0 },
      "confidence": 1
    },
    "angry": { "type": "noul", "noul": 0.19 }
  },
  "usage": { "input_tokens": 367, "output_tokens": 56 }
}

The charge is in the X-ArcRouter-Charge-USDC header, as with every other endpoint. The example above costs about $0.000016.

Paying

Both rails work. Send a prepaid key as a Bearer token, or send no key and pay the x402 challenge. Only input tokens are billed; output is free.