Module graph 

Available on crate feature graph only.

Graph-based workflow engine (LangGraph-inspired).

Build complex agent workflows with:

• StateGraph - Graph builder with nodes and edges
• GraphAgent - ADK Agent integration
• Checkpointer - Persistent state for human-in-the-loop
• Router - Conditional edge routing helpers
• Cycle support with recursion limits
• Streaming execution modes

Available with feature: graph

Modules

agent

GraphAgent - ADK Agent integration for graph workflows

cachenode-cache

Node-level caching for graph execution.

checkpoint

Checkpointing for persistent graph state

child

Invoking a node from inside another node’s body.

deferred

Deferred node (fan-in barrier) support for graph workflows.

deltadelta-checkpoint

Delta checkpoint compression for graph state.

edge

Edge types for graph control flow

error

Error types for adk-graph

executor

Pregel-based execution engine for graphs

functionalfunctional

Functional API for Graph Workflows

graph

StateGraph builder for constructing graphs

interrupt

Human-in-the-loop interrupt types

node

Node types for graph execution

prelude

Prelude module for convenient imports

retry

Per-node retry with exponential backoff.

state

State management for graph execution

stream

Streaming types for graph execution

subgraph

Running one graph as a node of another.

time_traveltime-travel

Time-travel debugging for graph execution history.

timeout

Timeout enforcement for graph node execution.

tool

Exposing a node or a whole graph as a tool an LLM can call.

Structs

AgentNode

Wrapper to use an existing ADK Agent as a graph node

AppendReducerfunctional

Built-in reducer: append to a Vec (list concatenation).

Channel

Channel definition for a state field

Checkpoint

Checkpoint data structure for persistence

CompiledGraph

A compiled graph ready for execution

DeferredNodeConfig

Configuration for a deferred (fan-in) node.

DeltaCheckpointerdelta-checkpoint

Wraps any Checkpointer with delta compression.

DeltaConfigdelta-checkpoint

Configuration for delta-based checkpoint compression.

ExecutionConfig

Configuration passed to nodes during execution

ExecutionLogfunctional

Tracks task completion status within a workflow run. Stored as part of the checkpoint metadata.

FanInTracker

Tracks which upstream paths have completed for a deferred node.

FunctionNode

Function node - wraps an async function as a node

GraphAgent

GraphAgent wraps a CompiledGraph as an ADK Agent

GraphAgentBuilder

Builder for GraphAgent

GraphToolConfirmationPause

A persisted tool-authorization pause emitted by a graph.

InterruptedExecution

Information about an interrupted execution

MapDeltadelta-checkpoint

Delta representation for HashMap<String, Value>.

MemoryCheckpointer

In-memory checkpointer for development and testing

MergeReducerfunctional

Built-in reducer: deep merge for JSON-like structures.

MessagesValuefunctional

Chat message container with ID-based deduplication.

NodeCachenode-cache

Node cache that stores and retrieves execution results.

NodeCachePolicynode-cache

Cache policy for a graph node.

NodeContext

Context passed to nodes during execution

NodeOutput

Output from a node execution

PregelExecutor

Pregel-based executor for graphs

ProgressHandle

A shared progress handle that nodes can use to report progress, resetting the idle timeout counter.

ReducedValuefunctional

Append-only state container. Accumulates values across tasks. Persisted to checkpoints on each task completion.

ReplaceReducerfunctional

Built-in reducer: replace with incoming value (last-write-wins).

Router

Router helper functions for common patterns

StateGraph

Builder for constructing graphs

StateSchema

State schema defines channels and their reducers

StateSchemaBuilder

Builder for StateSchema

StateSchemaValidatorfunctional

Validates workflow state against a declared schema.

StepInfotime-travel

Information about a single execution step in the graph history.

StringDeltadelta-checkpoint

Delta representation for String.

TaskContextfunctional

Runtime context passed to #[entrypoint] and #[task] functions.

TimeTravelHandletime-travel

Handle for time-travel operations on a graph thread.

TimeoutPolicy

Timeout configuration for a graph node.

UntrackedValuefunctional

Transient runtime value excluded from checkpoints.

VecDeltadelta-checkpoint

Delta representation for Vec<Value>.

Enums

CacheBackendnode-cache

Cache backend selection.

CheckpointTypedelta-checkpoint

Discriminates between full state snapshots and incremental delta records.

Edge

Edge type

EdgeTarget

Target of an edge

ExpectedTypefunctional

Expected JSON value type for a state field.

FunctionalErrorfunctional

Errors specific to the functional API.

GraphError

Errors that can occur during graph operations

Interrupt

Interrupt request from a node or configuration

MergeStrategy

How to combine outputs from multiple upstream parallel paths.

OnTimeout

Recovery action when a node times out.

Reducer

Reducer determines how state updates are merged

StreamEvent

Events emitted during streaming

StreamMode

Stream mode options

StringOpdelta-checkpoint

An individual edit operation for string diffs.

Constants

END

START

Special node identifiers

Traits

Checkpointer

Checkpointer trait for persistence

Diffdelta-checkpoint

Trait for types that can compute and apply incremental diffs.

Node

A node in the graph

TypedReducerfunctional

Trait for defining custom merge strategies for state values.

Functions

compute_cache_keynode-cache

Computes a deterministic cache key from a node name and its input state.

execute_with_timeout

Execute a node with timeout enforcement.

interrupt

Helper to create a dynamic interrupt from within a node

interrupt_with_data

Helper to create a dynamic interrupt with data

Type Aliases

Result

Result type for graph operations

State

Graph state - a map of channel names to values