StdOutCallbackHandler

Run on new output token.

Run when LLM ends running.

Run when LLM errors.

Run on each protocol event from stream_events(version="v3").

Run when chain errors.

Run when tool errors.

Run when Retriever errors.

Run when Retriever ends running.

Run when LLM starts running.

Run when a chat model starts running.

Run when the Retriever starts running.

Run when the tool starts running.

Run on a retry event.

Override to define a handler for a custom event.