# add_json_output_arg

> **Function** in `deepagents_cli`

📖 [View in docs](https://reference.langchain.com/python/deepagents-cli/output/add_json_output_arg)

Add a `--json` flag to an argparse parser.

## Signature

```python
add_json_output_arg(
    parser: argparse.ArgumentParser,
    *,
    default: OutputFormat | None = None,
) -> None
```

## Parameters

| Name | Type | Required | Description |
|------|------|----------|-------------|
| `parser` | `argparse.ArgumentParser` | Yes | Parser to update. |
| `default` | `OutputFormat \| None` | No | Default output format for this parser.  Pass `None` for subparsers so parent parser values are preserved. (default: `None`) |

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[View source on GitHub](https://github.com/langchain-ai/deepagents/blob/a827cddf72d72e4b17921b8eb445a3bfb0511cb4/libs/cli/deepagents_cli/output.py#L18)