LangChain Reference home pageLangChain ReferenceLangChain Reference
  • GitHub
  • Main Docs
Deep Agents
LangChain
LangGraph
Integrations
LangSmith
  • Overview
  • Graphs
  • Functional API
  • Pregel
  • Checkpointing
  • Storage
  • Caching
  • Types
  • Runtime
  • Config
  • Errors
  • Constants
  • Channels
  • Agents
LangGraph CLI
LangGraph SDK
LangGraph Supervisor
LangGraph Swarm
⌘I

LangChain Assistant

Ask a question to get started

Enter to send•Shift+Enter new line

Menu

OverviewGraphsFunctional APIPregelCheckpointingStorageCachingTypesRuntimeConfigErrorsConstantsChannelsAgents
LangGraph CLI
LangGraph SDK
LangGraph Supervisor
LangGraph Swarm
Language
Theme
Pythonlanggraphpregelprotocol
Module●Since v0.2

protocol

Attributes

attribute
All: Literal['*']

Special value to indicate that graph should interrupt on all nodes.

attribute
StreamMode: Literal['values', 'updates', 'checkpoints', 'tasks', 'debug', 'messages', 'custom']

How the stream method should emit outputs.

  • "values": Emit all values in the state after each step, including interrupts. When used with functional API, values are emitted once at the end of the workflow.
  • "updates": Emit only the node or task names and updates returned by the nodes or tasks after each step. If multiple updates are made in the same step (e.g. multiple nodes are run) then those updates are emitted separately.
  • "custom": Emit custom data using from inside nodes or tasks using StreamWriter.
  • "messages": Emit LLM messages token-by-token together with metadata for any LLM invocations inside nodes or tasks.
  • "checkpoints": Emit an event when a checkpoint is created, in the same format as returned by get_state().
  • "tasks": Emit events when tasks start and finish, including their results and errors.
  • "debug": Emit "checkpoints" and "tasks" events for debugging purposes.
attribute
ContextT

Type variable used to represent graph run scoped context.

Defaults to None.

attribute
InputT

Type variable used to represent the input to a StateGraph.

Defaults to StateT.

attribute
OutputT

Type variable used to represent the output of a StateGraph.

Defaults to StateT.

attribute
StateT

Type variable used to represent the state in a graph.

attribute
StreamChunk: tuple[tuple[str, ...], str, Any]

Classes

class
Command

One or more commands to update the graph's state and send messages to nodes.

class
StateSnapshot

Snapshot of the state of the graph at the beginning of a step.

class
StateUpdate
class
PregelProtocol
class
StreamProtocol
View source on GitHub