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

# unknown_model

> HTTP 400 on POST /v1/runs: a decision run named a model other than neon-1.1 or neon-latest. Which model ids are accepted and how to fix it.

`unknown_model` means a decision run set the optional `model` field to a value OpenType does not serve. Read this page if you pin a model id in your requests.

| HTTP  | `code`          | Retryable                   |
| ----- | --------------- | --------------------------- |
| `400` | `unknown_model` | No. Fix the model id first. |

## What happened

Route: `POST /v1/runs` with `"kind": "decision"`.

Decision runs accept an optional `model` field. OpenType serves one model, Neon 1.1, under two ids:

| `model`       | Meaning          |
| ------------- | ---------------- |
| `neon-1.1`    | Neon 1.1, pinned |
| `neon-latest` | Neon 1.1         |
| omitted       | Neon 1.1         |

The request named something else, such as a misspelled id or another vendor's model name. The run was refused before it existed. Nothing was stored and nothing was charged.

## How to fix

* Set `model` to `neon-1.1` or `neon-latest`, or leave it out.
* Copy the id exactly as written here: `neon-1.1` or `neon-latest`.
* Send the corrected request. It was refused before a run existed, so you may keep the same `Idempotency-Key`.

A live decision response reports the model that answered in `decision.model`, which reads `neon-1.1`.

## Example

The message text is not fixed. Branch on `code`.

```json theme={"system"}
{"error":{"code":"unknown_model","message":"...","request_id":"req_7d3f0c1a9b2e4f6a8c0d1e2f3a4b5c6d"}}
```

A decision run that pins the model:

<CodeGroup>
  ```bash curl theme={"system"}
  curl https://api.opentype.dev/v1/runs \
    -H "Authorization: Bearer $OPENTYPE_API_KEY" \
    -H "Content-Type: application/json" \
    -H "Idempotency-Key: ticket-4822-triage" \
    -d '{
      "kind": "decision",
      "model": "neon-1.1",
      "state": {"ticket": "I was charged twice this month."},
      "questions": {"urgent": {"type": "noul", "instructions": "reply within the hour?"}},
      "max_output_tokens": 16
    }'
  ```

  ```typescript TypeScript theme={"system"}
  const res = await fetch("https://api.opentype.dev/v1/runs", {
    method: "POST",
    headers: {
      Authorization: `Bearer ${process.env.OPENTYPE_API_KEY}`,
      "Content-Type": "application/json",
      "Idempotency-Key": "ticket-4822-triage",
    },
    body: JSON.stringify({
      kind: "decision",
      model: "neon-1.1", // or "neon-latest", or omit
      state: { ticket: "I was charged twice this month." },
      questions: { urgent: { type: "noul", instructions: "reply within the hour?" } },
      max_output_tokens: 16,
    }),
  });

  const body = await res.json();
  if (!res.ok) throw new Error(`${body.error.code} (${body.error.request_id})`);
  console.log(body.decision.model); // "neon-1.1"
  ```

  ```python Python theme={"system"}
  import os
  import requests

  resp = requests.post(
      "https://api.opentype.dev/v1/runs",
      headers={
          "Authorization": f"Bearer {os.environ['OPENTYPE_API_KEY']}",
          "Content-Type": "application/json",
          "Idempotency-Key": "ticket-4822-triage",
      },
      json={
          "kind": "decision",
          "model": "neon-1.1",  # or "neon-latest", or omit
          "state": {"ticket": "I was charged twice this month."},
          "questions": {"urgent": {"type": "noul", "instructions": "reply within the hour?"}},
          "max_output_tokens": 16,
      },
      timeout=60,
  )

  body = resp.json()
  if not resp.ok:
      raise RuntimeError(f"{body['error']['code']} ({body['error']['request_id']})")
  print(body["decision"]["model"])  # "neon-1.1"
  ```
</CodeGroup>

## Related

* [Models and pricing](/getting-started/models-and-pricing) - Neon 1.1, its ids and its prices.
* [Decision runs](/guides/decision-runs) - every field of a decision request.
* [invalid\_body](/problems/invalid_body) - other fields that do not fit the run contract.
* [Problem codes](/problems) - every code, its status, and whether a retry can help.