# NovaSystemTool

> **Class** in `langchain_aws`

📖 [View in docs](https://reference.langchain.com/python/langchain-aws/tools/nova_tools/NovaSystemTool)

Base class for Nova system tools.

System tools are built-in tools provided by Nova models that execute
server-side within the Bedrock API. Unlike custom tools, system tools
don't require client-side implementation — the model invokes them
internally, and results are returned as part of the response.

This class extends ``BaseTool`` so that system tools are accepted by
LangGraph's ``ToolNode`` and ``create_react_agent``. During normal
operation, ``_run`` is never called because the Bedrock API returns
system tool results as ``server_tool_use`` / ``server_tool_result``
content blocks, which do not appear in ``AIMessage.tool_calls``.

## Signature

```python
NovaSystemTool()
```

## Parameters

| Name | Type | Required | Description |
|------|------|----------|-------------|
| `name` | `unknown` | Yes | The name of the system tool (e.g., "nova_grounding"). |
| `description` | `unknown` | Yes | A description of the system tool. |

## Extends

- `BaseTool`

## Properties

- `type`
- `args_schema`

## Methods

- [`to_bedrock_format()`](https://reference.langchain.com/python/langchain-aws/tools/nova_tools/NovaSystemTool/to_bedrock_format)

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[View source on GitHub](https://github.com/langchain-ai/langchain-aws/blob/10d18256d46953e5fc8dca313a2c41eee29c2a80/libs/aws/langchain_aws/tools/nova_tools.py#L126)