# get_prompt_input_key

> **Function** in `langchain_classic`

📖 [View in docs](https://reference.langchain.com/python/langchain-classic/memory/utils/get_prompt_input_key)

Get the prompt input key.

## Signature

```python
get_prompt_input_key(
    inputs: dict[str, Any],
    memory_variables: list[str],
) -> str
```

## Parameters

| Name | Type | Required | Description |
|------|------|----------|-------------|
| `inputs` | `dict[str, Any]` | Yes | Dict[str, Any] |
| `memory_variables` | `list[str]` | Yes | List[str] |

## Returns

`str`

A prompt input key.

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[View source on GitHub](https://github.com/langchain-ai/langchain/blob/f0c5a28fa05adcda89aebcb449d897245ab21fa4/libs/langchain/langchain_classic/memory/utils.py#L4)