# Nova Act model version selection
<a name="model-version-selection"></a>

The Nova Act service relies on a custom foundation model, specially trained for UI-forward applications such as browser automation, tool use, and Human-in-the-Loop.

We release models under two support levels:
+  **General Availability (GA)** - Stable releases for production applications, supported for at least 1 year.
+  **Preview** - Preview releases that give you an opportunity to try out new functionality and model performance.

There are two approaches for selecting the model version for your workflow:
+  **Automatically track to the latest version** 
  + Select the `nova-act-latest` alias to automatically use the latest GA model version.
  + Select the `nova-act-preview` alias to automatically use the latest preview model.
+  **Pin to a specific model version** - Select a specific model version that will be supported for at least 1 year.

**Note**  
 `nova-act-latest` only tracks GA models and will never automatically update to a preview model.  
Preview models are not version-pinnable. Use `nova-act-preview` to access the latest preview release.

## Available model selection IDs
<a name="available-model-selection-ids"></a>


| Model-Id | Description | 
| --- | --- | 
|  `nova-act-latest`  | Alias to the latest GA model. Your workflows automatically track the latest GA model that your Nova Act SDK version supports. | 
|  `nova-act-preview`  | Alias to the latest preview model (currently v1.1). Your workflow automatically tracks the latest preview model that your Nova Act SDK supports.<br /> **Note:** If the latest preview model requires a newer SDK version than you’re using, you’ll get the most recent GA model that your SDK supports, along with a warning message. | 
|  `nova-act-v1.0`  | The GA model released on December 2, 2025. This is the first example of a pinable model selection ID. | 

**Note**  
At launch (December 2, 2025), all three model IDs point to the same v1.0 model. The aliases automatically track newer versions as they become available.

## Model Selection Options
<a name="model-selection-options"></a>

Specify the model version using the ** `model_id` ** parameter in your workflow definition. The following example uses ** `model_id="nova-act-latest"` **:

```
from nova_act import NovaAct, workflow

@workflow(workflow_definition_name="<your-workflow-name-here>", model_id="nova-act-latest")
def explore_travel_destinations():
    """Explore travel destinations."""
    with NovaAct(starting_page="https://nova.amazon.com/act/gym") as nova:
        nova.act("Click on NextDot, then explore possible destinations.")
```