langchain.callbacks.streamlit.__init__.StreamlitCallbackHandler¶
- langchain.callbacks.streamlit.__init__.StreamlitCallbackHandler(parent_container: DeltaGenerator, *, max_thought_containers: int = 4, expand_new_thoughts: bool = True, collapse_completed_thoughts: bool = True, thought_labeler: Optional[LLMThoughtLabeler] = None) BaseCallbackHandler[source]¶
Callback Handler that writes to a Streamlit app.
This CallbackHandler is geared towards use with a LangChain Agent; it displays the Agent’s LLM and tool-usage “thoughts” inside a series of Streamlit expanders.
- Parameters
parent_container – The st.container that will contain all the Streamlit elements that the Handler creates.
max_thought_containers – The max number of completed LLM thought containers to show at once. When this threshold is reached, a new thought will cause the oldest thoughts to be collapsed into a “History” expander. Defaults to 4.
expand_new_thoughts – Each LLM “thought” gets its own st.expander. This param controls whether that expander is expanded by default. Defaults to True.
collapse_completed_thoughts – If True, LLM thought expanders will be collapsed when completed. Defaults to True.
thought_labeler – An optional custom LLMThoughtLabeler instance. If unspecified, the handler will use the default thought labeling logic. Defaults to None.
- Returns
A new StreamlitCallbackHandler instance.
Note that this is an “auto-updating” API (if the installed version of Streamlit)
has a more recent StreamlitCallbackHandler implementation, an instance of that class
will be used.