Agent Configuration Reference

All fields available on Agent.builder().

Field	Type	Required	Default	Description
role	String	Yes	—	The agent’s role/title. Used in prompts and logging.
goal	String	Yes	—	The agent’s primary objective. Included in the system prompt.
background	String	No	null	Persona context for the system prompt. Omitted when null or blank.
tools	List<Object>	No	[]	Tools available to this agent. Each entry must implement AgentTool or have @Tool-annotated methods.
llm	ChatModel	Yes	—	Any LangChain4j ChatModel.
allowDelegation	boolean	No	false	When true, a delegate tool is auto-injected at execution time.
verbose	boolean	No	false	When true, prompts and LLM responses are logged at INFO level.
maxIterations	int	No	25	Maximum number of tool-call iterations before the agent is forced to produce a final answer. Must be greater than zero.
responseFormat	String	No	""	Extra formatting instructions appended to the system prompt.

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Validation

The following validations are applied at build() time:

• role must not be null or blank
• goal must not be null or blank
• llm must not be null
• maxIterations must be greater than zero
• Each tool must implement AgentTool or have at least one @Tool-annotated method

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Example

Agent agent = Agent.builder()
    .role("Senior Research Analyst")
    .goal("Find accurate, well-structured information on any topic")
    .background("You are a veteran researcher with 15 years of technology industry experience.")
    .tools(List.of(new WebSearchTool()))
    .llm(model)
    .allowDelegation(true)
    .verbose(false)
    .maxIterations(25)
    .responseFormat("Always structure your response with clear headings.")
    .build();

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Immutability

Agent is an immutable value object. Use toBuilder() to create modified copies:

Agent verboseAgent = agent.toBuilder().verbose(true).build();