Auditable |
Base class |
Marker class for auto-logged events |
Event |
Base class |
Subclass to define events (auto-frozen) |
EventGraph |
Class |
Build and run the event-driven graph |
EventGraph.invoke() |
Method |
Run graph synchronously, returns EventLog |
EventGraph.ainvoke() |
Method |
Async version of invoke() |
EventGraph.stream_events() |
Method |
Yield events as produced; optional reducer snapshots via StreamFrame |
EventGraph.astream_events() |
Method |
Async version of stream_events(); supports include_llm_tokens=True (LLMToken/LLMStreamEnd) and include_custom_events=True (CustomEventFrame/StateSnapshotFrame) |
EventGraph.stream_resume() |
Method |
Yield events during resume; streaming equivalent of resume() |
EventGraph.astream_resume() |
Method |
Async version of stream_resume(); supports include_llm_tokens=True (LLMToken/LLMStreamEnd) and include_custom_events=True (CustomEventFrame/StateSnapshotFrame) |
EventGraph.resume() |
Method |
Resume interrupted graph with a domain event (requires checkpointer) |
EventGraph.aresume() |
Method |
Async version of resume() |
EventGraph.get_state() |
Method |
Get GraphState for a checkpointed thread |
EventGraph.compiled |
Property |
Access underlying CompiledStateGraph for advanced LangGraph patterns |
EventGraph.reducer_names |
Property |
frozenset of registered reducer names |
EventGraph.mermaid() |
Method |
Return a Mermaid flowchart of event correlations |
emit_custom |
Function |
Emit a LangGraph custom stream event from a handler |
aemit_custom |
Function |
Async variant of emit_custom for async handlers |
emit_state_snapshot |
Function |
Emit a typed state snapshot stream frame from a handler |
aemit_state_snapshot |
Function |
Async variant of emit_state_snapshot for async handlers |
STATE_SNAPSHOT_EVENT_NAME |
Constant |
Protocol name used for snapshot custom events ("intermediate_state") |
EventLog |
Class |
Immutable query container over events |
GraphState |
NamedTuple |
(events, is_interrupted, interrupted) from get_state() |
Halted |
Event |
Signal immediate graph termination; subclass for domain-specific halts |
MaxRoundsExceeded |
Event |
Halted subtype emitted when max_rounds is exceeded (rounds: int) |
Cancelled |
Event |
Halted subtype emitted when async handler is cancelled |
Interrupted |
Base class |
Bare marker — subclass with typed fields to pause graph |
MessageEvent |
Base class |
Mixin for events wrapping LangChain messages |
message_reducer |
Function |
Built-in reducer for MessageEvent projection |
on |
Decorator |
Subscribe a handler to one or more event types |
Reducer |
Class |
Map events to a named LangGraph state channel |
ScalarReducer |
Class |
Last-write-wins reducer for single values (None is a valid value) |
SKIP |
Sentinel |
Return from ScalarReducer fn to leave value unchanged |
Resumed |
Event |
Created on resume with the dispatched event and interrupted backref |
Scatter |
Class |
Fan-out into multiple events; generic Scatter[T] annotates the produced type |
StreamFrame |
NamedTuple |
(event, reducers) yielded by stream_events() with include_reducers |
LLMToken |
NamedTuple |
(run_id, content) token delta yielded by async streams with include_llm_tokens=True |
LLMStreamEnd |
NamedTuple |
(run_id, message_id) marker yielded when an LLM stream completes |
CustomEventFrame |
NamedTuple |
(name, data) custom payload yielded from LangGraph on_custom_event with include_custom_events=True |
StateSnapshotFrame |
NamedTuple |
(data) typed snapshot frame yielded when on_custom_event uses STATE_SNAPSHOT_EVENT_NAME |
SystemPromptSet |
Event |
Built-in MessageEvent for system prompts |
OrphanedEventWarning |
Warning |
Issued at graph construction when return types have no subscriber |