Package com.google.adk.agents

Class LoopAgent

java.lang.Object

com.google.adk.workflow.BaseNode

com.google.adk.agents.BaseAgent

com.google.adk.agents.LoopAgent

All Implemented Interfaces:

Node

public class LoopAgent
extends BaseAgent

An agent that runs its sub-agents sequentially in a loop.

The loop continues until a sub-agent escalates, or until the maximum number of iterations is reached (if specified).

Composition with LlmAgents: a LoopAgent does not transfer control back to a parent LlmAgent. To react to loop results, place the LoopAgent and the follow-up LlmAgent as siblings inside a SequentialAgent. Loop sub-agents publish via outputKey and the follow-up reads via {key} placeholders in its instruction:

 var refiner =
     LlmAgent.builder()
         .name("refiner")
         .model("gemini-flash-latest")
         .instruction("Refine: {draft?}")
         .outputKey("draft")
         .build();
 var publisher =
     LlmAgent.builder()
         .name("publisher")
         .model("gemini-flash-latest")
         .instruction("Publish: {draft}")
         .build();
 var loop =
     LoopAgent.builder().name("loop").subAgents(refiner).maxIterations(3).build();
 var root = SequentialAgent.builder().name("root").subAgents(loop, publisher).build();
 

Nested Class Summary

Nested Classes

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

Method Summary

Modifier and Type	Method	Description
static LoopAgent.Builder	builder()
static LoopAgent	fromConfig(LoopAgentConfig config, String configAbsPath)	Creates a LoopAgent from configuration.
@Nullable Integer	maxIterations()
protected io.reactivex.rxjava3.core.Flowable<Event>	runAsyncImpl(InvocationContext invocationContext)	Agent-specific asynchronous logic.
protected io.reactivex.rxjava3.core.Flowable<Event>	runLiveImpl(InvocationContext invocationContext)	Agent-specific synchronous logic.

Methods inherited from class com.google.adk.agents.BaseAgent

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

Methods inherited from class com.google.adk.workflow.BaseNode

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

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.google.adk.workflow.Node

requiresAllPredecessors

Method Details

builder

public static LoopAgent.Builder builder()

fromConfig

public static LoopAgent fromConfig(LoopAgentConfig config,
 String configAbsPath)
                            throws ConfigAgentUtils.ConfigurationException

Creates a LoopAgent from configuration.

Parameters:

config - The agent configuration.

configAbsPath - The absolute path to the agent config file.

Returns:

the configured LoopAgent

Throws:

ConfigAgentUtils.ConfigurationException - if the configuration is invalid

runAsyncImpl

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

Description copied from class: BaseAgent

Agent-specific asynchronous logic.

Specified by:

runAsyncImpl in class BaseAgent

Parameters:

invocationContext - Current invocation context.

Returns:

stream of agent-generated events.

runLiveImpl

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

Description copied from class: BaseAgent

Agent-specific synchronous logic.

Specified by:

runLiveImpl in class BaseAgent

Parameters:

invocationContext - Current invocation context.

Returns:

stream of agent-generated events.

maxIterations

public @Nullable Integer maxIterations()