---
title: Define a model by hand
description: Write and validate the compact JSON yourself, then submit it with each execution.
icon: pencil-ruler
---

A model is readable JSON. You can write one from scratch, or take a generated one and edit it.

```bash
curl https://api.aityx.ai/v1/systemtwo/models \
  -H "Authorization: Bearer $AITYX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "output": {
      "is_urgent": { "type": "noul", "instructions": "Does this ticket need priority review?" }
    },
    "content": {
      "name": "ticket triage",
      "inputs": {
        "issue ongoing": { "type": "boolean", "desc": "Is the problem still happening?", "from": "tense and time words" },
        "business impact": {
          "type": "none|degraded|blocked",
          "desc": "How much of normal operation is affected?",
          "options": { "none": "no effect", "degraded": "slower or partial", "blocked": "a core operation cannot complete" },
          "from": "what the customer says they cannot do"
        }
      },
      "decisions": {
        "is_urgent": {
          "type": "boolean",
          "desc": "Priority review is needed when an ongoing issue blocks a core operation.",
          "table": [
            ["issue ongoing", "business impact", "=> boolean", "# why"],
            ["true",  "blocked", "true",  "an ongoing incident is blocking a core operation"],
            ["-",     "-",       "false", "nothing indicates an ongoing, blocking incident"]
          ]
        }
      }
    }
  }'
```

The definition passes the same checks a generated one does: format, strict lint, the question contract against
`output`, expansion, validation and compilation. The validation response reports `valid` and the result
of each stage. Inspect its errors and warnings before executing the definition.

Manual validation uses the same endpoint with `content` and `output`, without a prompt or files. It is
free and returns a stage report rather than saving a model. Check `valid` even when the HTTP status is
200. When valid, package the definition and the question contract you supplied as `{content, questions}`.

For execution, submit that complete object in `model` and the case in `state` to `POST /v1/systemone`:

```js
const model = { content: checkedContent, questions: output };
const body = JSON.stringify({ model, state });
```

Matching JSON uses System One pricing. The [code guide](/docs/guides/call-from-code) shows a complete client.

The format is specified in [Model format](/docs/resources/model-format). The console's editor works on the current
session definition. Keep your original file and download the edited one; no server-managed version is created.