StreamlitCallbackHandler

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. expand_new_thoughts Each LLM "thought" gets its own st.expander. This param controls whether that expander is expanded by default. collapse_completed_thoughts If True, LLM thought expanders will be collapsed when completed. thought_labeler An optional custom LLMThoughtLabeler instance. If unspecified, the handler will use the default thought labeling logic.

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.