StreamEvent

Event data.

The contents of the event data depend on the event type.

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 -- LangChain tools
• chain - most Runnables 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.

Metadata associated with the runnable that generated this event.

The name of the runnable that generated the event.

An randomly generated ID to keep track of the execution of the given runnable.

Each child runnable that gets invoked as part of the execution of a parent runnable is assigned its own unique ID.

Tags associated with the runnable that generated this event. Tags are always inherited from parent runnables.