event

Event names are of the format: on_[runnable_type]_(start|stream|end).

Runnable types are one of:

• llm - used by non chat models
• chat_model - used by chat models
• prompt -- e.g., ChatPromptTemplate
• tool -- from tools defined via @tool decorator or inheriting from Tool/BaseTool
• chain - most Runnable objects are of this type

Further, the events are categorized as one of:

• start - when the Runnable starts
• stream - when the Runnable is streaming
• *end - when the Runnable ends

start, stream and end are associated with slightly different data payload.

Please see the documentation for EventData for more details.