> ## Documentation Index
> Fetch the complete documentation index at: https://docs.upsonic.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# User Input Fields

> Specify which fields require user input

## Overview

Specify which fields require user input.

## Usage

```python theme={null}
from upsonic.tools import tool

@tool(
    requires_user_input=True,
    user_input_fields=["api_key"]
)
def api_call(endpoint: str, api_key: str) -> str:
    """
    Make an API call with user-provided key.

    Args:
        endpoint: API endpoint URL
        api_key: API authentication key

    Returns:
        API response
    """
    return f"API call to {endpoint} completed"
```

## Parameters

* `user_input_fields` (List\[str]): List of field names that require user input