# Get a Playground problem set

```http
GET /api/public/v1/competitions/mathematics-distillation-challenge-equational-theories-stage1/playground/problem-sets/{problemSetId}
```

**Scope**: `playground.read`.

Returns the current ordered snapshot of one Stage 1 practice problem set. This endpoint is not paginated; `items.length` matches the summary `count` returned by [List Playground problem sets](./list-playground-problem-sets.md).

Use each item's zero-based `index` with the returned `id` when [creating a Playground Run](./create-playground-run.md). Run creation resolves and stores the selected equations and expected answer, so later catalog changes do not alter an already-created Run.

## Path parameters

| Parameter | Type | Required | Description |
| :--- | :--- | :---: | :--- |
| `problemSetId` | string | Yes | Problem-set ID returned by the list endpoint. |

## Response fields

| Field | Type | Description |
| :--- | :--- | :--- |
| `id` | string | Problem-set ID to send as `problems[].problemSet`. |
| `title` | string | Human-readable title; falls back to `id` when no title is configured. |
| `items` | [EquationProblem](#equation-problem-fields)[] | Valid problems in stable index order for this snapshot. |

### Equation problem fields

| Field | Type | Description |
| :--- | :--- | :--- |
| `index` | integer | Zero-based index to send as `problems[].index`. |
| `equation1` | string | First equation presented to the model. |
| `equation2` | string | Second equation presented to the model. |
| `goldAnswer` | boolean | Public expected answer used to score this practice problem. It is not included in the model prompt. |

## Example request

```bash
curl "https://api.sair.foundation/api/public/v1/competitions/mathematics-distillation-challenge-equational-theories-stage1/playground/problem-sets/pset_hard3" \
  -H "Authorization: Bearer $SAIR_API_KEY"
```

## Example response

```json
{
  "ok": true,
  "data": {
    "id": "pset_hard3",
    "title": "Hard problem set 3",
    "items": [
      {
        "index": 0,
        "equation1": "x + y = y + x",
        "equation2": "y + x = x + y",
        "goldAnswer": true
      }
    ]
  }
}
```

## Errors

See [Errors](../../../errors.md). A missing or unavailable problem set returns `404 NOT_FOUND`. An unavailable competition also returns `404 NOT_FOUND`.