Class SequentialAgent

java.lang.Object

com.google.adk.agents.BaseAgent

com.google.adk.agents.SequentialAgent

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, description, findAgent, findSubAgent, fromConfig, name, parentAgent, parentAgent, rootAgent, runAsync, runLive, 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.
final String	description()	Gets the one-line description of the agent's capability.
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.
final String	name()	Gets the agent's unique name.
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.
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 Object

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

Method Details

builder

public static SequentialAgent.Builder builder()

runAsyncImpl

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

Runs sub-agents sequentially.

When resumability is enabled, on resume execution fast-forwards to the sub-agent being resumed (completed ones are not re-run) and pauses on a pending long-running call; when disabled, sub-agents simply run in order (matches Python ADK v1 with resumability off). Temporary, event-based.

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