# SchemaAnnotationError

> **Class** in `langchain_core`

📖 [View in docs](https://reference.langchain.com/python/langchain-core/tools/base/SchemaAnnotationError)

Raised when `args_schema` is missing or has an incorrect type annotation.

## Signature

```python
SchemaAnnotationError()
```

## Extends

- `TypeError`

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[View source on GitHub](https://github.com/langchain-ai/langchain/blob/b302691ff9ad841804e93e5addbdc53b6974473b/libs/core/langchain_core/tools/base.py#L89)