# HumanApprovalCallbackHandler

> **Class** in `langchain_community`

📖 [View in docs](https://reference.langchain.com/python/langchain-community/callbacks/human/HumanApprovalCallbackHandler)

Callback for manually validating values.

## Signature

```python
HumanApprovalCallbackHandler(
    self,
    approve: Callable[[Any], bool] = _default_approve,
    should_check: Callable[[Dict[str, Any]], bool] = _default_true,
)
```

## Extends

- `BaseCallbackHandler`

## Constructors

```python
__init__(
    self,
    approve: Callable[[Any], bool] = _default_approve,
    should_check: Callable[[Dict[str, Any]], bool] = _default_true,
)
```

| Name | Type |
|------|------|
| `approve` | `Callable[[Any], bool]` |
| `should_check` | `Callable[[Dict[str, Any]], bool]` |


## Properties

- `raise_error`

## Methods

- [`on_tool_start()`](https://reference.langchain.com/python/langchain-community/callbacks/human/HumanApprovalCallbackHandler/on_tool_start)

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[View source on GitHub](https://github.com/langchain-ai/langchain-community/blob/4b280287bd55b99b44db2dd849f02d66c89534d5/libs/community/langchain_community/callbacks/human.py#L35)