langchain.callbacks.streaming_stdout_final_only.FinalStreamingStdOutCallbackHandler

class langchain.callbacks.streaming_stdout_final_only.FinalStreamingStdOutCallbackHandler(*, answer_prefix_tokens: Optional[List[str]] = None, strip_tokens: bool = True, stream_prefix: bool = False)[source]

Callback handler for streaming in agents. Only works with agents using LLMs that support streaming.

Only the final output of the agent will be streamed.

Instantiate FinalStreamingStdOutCallbackHandler.

Parameters
  • answer_prefix_tokens (Optional[List[str]]) – Token sequence that prefixes the answer. Default is [“Final”, “Answer”, “:”]

  • strip_tokens (bool) – Ignore white spaces and new lines when comparing answer_prefix_tokens to last tokens? (to determine if answer has been reached)

  • stream_prefix (bool) – Should answer prefix itself also be streamed?

Attributes

ignore_agent

Whether to ignore agent callbacks.

ignore_chain

Whether to ignore chain callbacks.

ignore_chat_model

Whether to ignore chat model callbacks.

ignore_llm

Whether to ignore LLM callbacks.

ignore_retriever

Whether to ignore retriever callbacks.

ignore_retry

Whether to ignore retry callbacks.

raise_error

run_inline

Methods

__init__(*[, answer_prefix_tokens, ...])

Instantiate FinalStreamingStdOutCallbackHandler.

append_to_last_tokens(token)

check_if_answer_reached()

on_agent_action(action, **kwargs)

Run on agent action.

on_agent_finish(finish, **kwargs)

Run on agent end.

on_chain_end(outputs, **kwargs)

Run when chain ends running.

on_chain_error(error, **kwargs)

Run when chain errors.

on_chain_start(serialized, inputs, **kwargs)

Run when chain starts running.

on_chat_model_start(serialized, messages, ...)

Run when LLM starts running.

on_llm_end(response, **kwargs)

Run when LLM ends running.

on_llm_error(error, **kwargs)

Run when LLM errors.

on_llm_new_token(token, **kwargs)

Run on new LLM token.

on_llm_start(serialized, prompts, **kwargs)

Run when LLM starts running.

on_retriever_end(documents, *, run_id[, ...])

Run when Retriever ends running.

on_retriever_error(error, *, run_id[, ...])

Run when Retriever errors.

on_retriever_start(serialized, query, *, run_id)

Run when Retriever starts running.

on_retry(retry_state, *, run_id[, parent_run_id])

Run on a retry event.

on_text(text, **kwargs)

Run on arbitrary text.

on_tool_end(output, **kwargs)

Run when tool ends running.

on_tool_error(error, **kwargs)

Run when tool errors.

on_tool_start(serialized, input_str, **kwargs)

Run when tool starts running.

__init__(*, answer_prefix_tokens: Optional[List[str]] = None, strip_tokens: bool = True, stream_prefix: bool = False) None[source]

Instantiate FinalStreamingStdOutCallbackHandler.

Parameters
  • answer_prefix_tokens (Optional[List[str]]) – Token sequence that prefixes the answer. Default is [“Final”, “Answer”, “:”]

  • strip_tokens (bool) – Ignore white spaces and new lines when comparing answer_prefix_tokens to last tokens? (to determine if answer has been reached)

  • stream_prefix (bool) – Should answer prefix itself also be streamed?

Return type

None

append_to_last_tokens(token: str) None[source]
Parameters

token (str) –

Return type

None

check_if_answer_reached() bool[source]
Return type

bool

on_agent_action(action: AgentAction, **kwargs: Any) Any

Run on agent action.

Parameters
Return type

Any

on_agent_finish(finish: AgentFinish, **kwargs: Any) None

Run on agent end.

Parameters
Return type

None

on_chain_end(outputs: Dict[str, Any], **kwargs: Any) None

Run when chain ends running.

Parameters
  • outputs (Dict[str, Any]) –

  • kwargs (Any) –

Return type

None

on_chain_error(error: BaseException, **kwargs: Any) None

Run when chain errors.

Parameters
  • error (BaseException) –

  • kwargs (Any) –

Return type

None

on_chain_start(serialized: Dict[str, Any], inputs: Dict[str, Any], **kwargs: Any) None

Run when chain starts running.

Parameters
  • serialized (Dict[str, Any]) –

  • inputs (Dict[str, Any]) –

  • kwargs (Any) –

Return type

None

on_chat_model_start(serialized: Dict[str, Any], messages: List[List[BaseMessage]], **kwargs: Any) None

Run when LLM starts running.

Parameters
  • serialized (Dict[str, Any]) –

  • messages (List[List[BaseMessage]]) –

  • kwargs (Any) –

Return type

None

on_llm_end(response: LLMResult, **kwargs: Any) None

Run when LLM ends running.

Parameters
Return type

None

on_llm_error(error: BaseException, **kwargs: Any) None

Run when LLM errors.

Parameters
  • error (BaseException) –

  • kwargs (Any) –

Return type

None

on_llm_new_token(token: str, **kwargs: Any) None[source]

Run on new LLM token. Only available when streaming is enabled.

Parameters
  • token (str) –

  • kwargs (Any) –

Return type

None

on_llm_start(serialized: Dict[str, Any], prompts: List[str], **kwargs: Any) None[source]

Run when LLM starts running.

Parameters
  • serialized (Dict[str, Any]) –

  • prompts (List[str]) –

  • kwargs (Any) –

Return type

None

on_retriever_end(documents: Sequence[Document], *, run_id: UUID, parent_run_id: Optional[UUID] = None, **kwargs: Any) Any

Run when Retriever ends running.

Parameters
  • documents (Sequence[Document]) –

  • run_id (UUID) –

  • parent_run_id (Optional[UUID]) –

  • kwargs (Any) –

Return type

Any

on_retriever_error(error: BaseException, *, run_id: UUID, parent_run_id: Optional[UUID] = None, **kwargs: Any) Any

Run when Retriever errors.

Parameters
  • error (BaseException) –

  • run_id (UUID) –

  • parent_run_id (Optional[UUID]) –

  • kwargs (Any) –

Return type

Any

on_retriever_start(serialized: Dict[str, Any], query: str, *, run_id: UUID, parent_run_id: Optional[UUID] = None, tags: Optional[List[str]] = None, metadata: Optional[Dict[str, Any]] = None, **kwargs: Any) Any

Run when Retriever starts running.

Parameters
  • serialized (Dict[str, Any]) –

  • query (str) –

  • run_id (UUID) –

  • parent_run_id (Optional[UUID]) –

  • tags (Optional[List[str]]) –

  • metadata (Optional[Dict[str, Any]]) –

  • kwargs (Any) –

Return type

Any

on_retry(retry_state: RetryCallState, *, run_id: UUID, parent_run_id: Optional[UUID] = None, **kwargs: Any) Any

Run on a retry event.

Parameters
  • retry_state (RetryCallState) –

  • run_id (UUID) –

  • parent_run_id (Optional[UUID]) –

  • kwargs (Any) –

Return type

Any

on_text(text: str, **kwargs: Any) None

Run on arbitrary text.

Parameters
  • text (str) –

  • kwargs (Any) –

Return type

None

on_tool_end(output: Any, **kwargs: Any) None

Run when tool ends running.

Parameters
  • output (Any) –

  • kwargs (Any) –

Return type

None

on_tool_error(error: BaseException, **kwargs: Any) None

Run when tool errors.

Parameters
  • error (BaseException) –

  • kwargs (Any) –

Return type

None

on_tool_start(serialized: Dict[str, Any], input_str: str, **kwargs: Any) None

Run when tool starts running.

Parameters
  • serialized (Dict[str, Any]) –

  • input_str (str) –

  • kwargs (Any) –

Return type

None