# Model-specific configuration

> For AI agents: the complete documentation index is at
> [https://docs.retrocast.com/llms.txt](https://docs.retrocast.com/llms.txt) — every page is also available as
> markdown by appending `.md` to its URL.

Some models accept additional configuration via `model_config`:

## Auto-ARIMA (`aarima`)

```json
{
  "model_config": {
    "model": "aarima",
    "config": { "season_length": 7 }
  }
}
```

- `season_length` (integer or null): Override automatic seasonal period detection.

## Auto-ETS (`aets`)

```json
{
  "model_config": {
    "model": "aets",
    "config": { "season_length": 12 }
  }
}
```

- `season_length` (integer or null): Override automatic seasonal period detection.

## Chronos-2 (`chronos-2`)

```json
{
  "model_config": {
    "model": "chronos-2",
    "config": { "is_global": true }
  }
}
```

- `is_global` (boolean, default false): Enable influence across the time-series — useful if all passed-in time-series are related (e.g., same product, different stores).