# BaseConversationalRetrievalChain

> **Class** in `langchain_classic`

📖 [View in docs](https://reference.langchain.com/python/langchain-classic/chains/conversational_retrieval/base/BaseConversationalRetrievalChain)

Chain for chatting with an index.

## Signature

```python
BaseConversationalRetrievalChain()
```

## Extends

- `Chain`

## Properties

- `combine_docs_chain`
- `question_generator`
- `output_key`
- `rephrase_question`
- `return_source_documents`
- `return_generated_question`
- `get_chat_history`
- `response_if_no_docs_found`
- `model_config`
- `input_keys`
- `output_keys`

## Methods

- [`get_input_schema()`](https://reference.langchain.com/python/langchain-classic/chains/conversational_retrieval/base/BaseConversationalRetrievalChain/get_input_schema)
- [`save()`](https://reference.langchain.com/python/langchain-classic/chains/conversational_retrieval/base/BaseConversationalRetrievalChain/save)

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[View source on GitHub](https://github.com/langchain-ai/langchain/blob/c59e83a1ffba63d709ea4847445845edd82085dc/libs/langchain/langchain_classic/chains/conversational_retrieval/base.py#L77)