Class SequentialAgent

java.lang.Object

com.google.adk.workflow.BaseNode

com.google.adk.agents.BaseAgent

com.google.adk.agents.SequentialAgent

All Implemented Interfaces:

Node

public class SequentialAgent
extends BaseAgent

An agent that runs its sub-agents sequentially.

Composition with LlmAgents: a SequentialAgent does not transfer control back to a parent LlmAgent. Use it as the root or transferred-to agent and place any follow-up LlmAgent as the next sibling. Upstream publishes via outputKey and downstream reads via {key} placeholders in its instruction:

var draft =
    LlmAgent.builder()
        .name("draft")
        .model("gemini-flash-latest")
        .instruction("Draft a summary.")
        .outputKey("draft")
        .build();
var reviewer =
    LlmAgent.builder()
        .name("reviewer")
        .model("gemini-flash-latest")
        .instruction("Polish the draft: {draft}")
        .build();
var pipeline =
    SequentialAgent.builder().name("pipeline").subAgents(draft, reviewer).build();

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	SequentialAgent.Builder	Builder for SequentialAgent.

Method Summary

Modifier and Type	Method	Description
static SequentialAgent.Builder	builder()
static SequentialAgent	fromConfig(SequentialAgentConfig config, String configAbsPath)	Creates a SequentialAgent from configuration.
protected io.reactivex.rxjava3.core.Flowable<Event>	runAsyncImpl(InvocationContext invocationContext)	Runs sub-agents sequentially.
protected io.reactivex.rxjava3.core.Flowable<Event>	runLiveImpl(InvocationContext invocationContext)	Runs sub-agents sequentially in live mode.

Methods inherited from class BaseAgent

afterAgentCallback, beforeAgentCallback, canonicalAfterAgentCallbacks, canonicalBeforeAgentCallbacks, close, findAgent, findSubAgent, fromConfig, parentAgent, parentAgent, rootAgent, runAsync, runLive, runNode, subAgents, toolOrigin

Modifier and Type	Method	Description
com.google.common.collect.ImmutableList<? extends Callbacks.AfterAgentCallback>	afterAgentCallback()
com.google.common.collect.ImmutableList<? extends Callbacks.BeforeAgentCallback>	beforeAgentCallback()
com.google.common.collect.ImmutableList<? extends Callbacks.AfterAgentCallback>	canonicalAfterAgentCallbacks()	The resolved afterAgentCallback field as a list.
com.google.common.collect.ImmutableList<? extends Callbacks.BeforeAgentCallback>	canonicalBeforeAgentCallbacks()	The resolved beforeAgentCallback field as a list.
io.reactivex.rxjava3.core.Completable	close()	Closes all sub-agents.
Optional<BaseAgent>	findAgent(String name)	Finds an agent (this or descendant) by name.
Optional<BaseAgent>	findSubAgent(String name)	Recursively search sub agent by name.
static BaseAgent	fromConfig(BaseAgentConfig config, String configAbsPath)	Creates a new agent instance from a configuration object.
BaseAgent	parentAgent()	Retrieves the parent agent in the agent tree.
protected void	parentAgent(BaseAgent parentAgent)	Sets the parent agent.
BaseAgent	rootAgent()	Returns the root agent for this agent by traversing up the parent chain.
io.reactivex.rxjava3.core.Flowable<Event>	runAsync(InvocationContext parentContext)	Runs the agent asynchronously.
io.reactivex.rxjava3.core.Flowable<Event>	runLive(InvocationContext parentContext)	Runs the agent synchronously.
io.reactivex.rxjava3.core.Flowable<Event>	runNode(Context context, @Nullable Object nodeInput)	Runs this agent as a workflow node through its BaseAgent.runAsync(InvocationContext) lifecycle, including its callbacks.
List<? extends BaseAgent>	subAgents()
AgentEnums.AgentOrigin	toolOrigin()	Returns the origin of the tool when this agent is used as a tool.

Methods inherited from class BaseNode

config, description, inputSchema, name, outputSchema, rerunOnResume, stateSchema, waitForOutput

Modifier and Type	Method	Description
NodeConfig	config()	Returns the node's retry policy and execution timeout.
String	description()	Returns what the node does, for humans and for a model that may call it.
Optional<com.google.genai.types.Schema>	inputSchema()	Returns the schema the node's input must match.
final String	name()	Returns the name that identifies the node within its graph.
Optional<com.google.genai.types.Schema>	outputSchema()	Returns the schema that the node's output value must match.
boolean	rerunOnResume()	Returns true if a resumed node runs again from scratch, rather than completing with the resuming answer as its output.
Optional<com.google.genai.types.Schema>	stateSchema()	Returns the schema declaring the state keys the node uses.
boolean	waitForOutput()	Returns true if the node stays re-triggerable until it produces an output or a route, instead of completing when its run completes.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface Node

requiresAllPredecessors

Modifier and Type	Method	Description
default boolean	requiresAllPredecessors()	Returns true if the node runs only once every predecessor has completed, receiving all their outputs keyed by node name, as a fan-in node does.

Method Details

builder

public static SequentialAgent.Builder builder()

runAsyncImpl

protected io.reactivex.rxjava3.core.Flowable<Event> runAsyncImpl(InvocationContext invocationContext)

Runs sub-agents sequentially.

Three modes: with resumability on, a resume fast-forwards to the checkpointed sub-agent and pauses on a long-running call; with the deprecated shim on, the same happens but the resume point is reconstructed from history and nothing is checkpointed; with neither, sub-agents just run in order.

Specified by:

runAsyncImpl in class BaseAgent

Parameters:

invocationContext - Invocation context.

Returns:

Flowable emitting events from sub-agents.

runLiveImpl

protected io.reactivex.rxjava3.core.Flowable<Event> runLiveImpl(InvocationContext invocationContext)

Runs sub-agents sequentially in live mode.

Specified by:

runLiveImpl in class BaseAgent

Parameters:

invocationContext - Invocation context.

Returns:

Flowable emitting events from sub-agents in live mode.

fromConfig

public static SequentialAgent fromConfig(SequentialAgentConfig config,
 String configAbsPath)
                                  throws ConfigAgentUtils.ConfigurationException

Creates a SequentialAgent from configuration.

Parameters:

config - the agent configuration

configAbsPath - The absolute path to the agent config file.

Returns:

the configured SequentialAgent

Throws:

ConfigAgentUtils.ConfigurationException - if the configuration is invalid