Package dev.langchain4j.service.tool

Interface ToolExecutionErrorHandler

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface ToolExecutionErrorHandler

Handler for ToolExecutionExceptions thrown by a ToolExecutor.

Currently, there are two ways to handle errors:

1. Throw an exception: this will stop the AI service flow.

2. Return a text message (e.g., an error description) that will be sent back to the LLM, allowing it to respond appropriately (for example, by correcting the error and retrying).

Since:

1.4.0

See Also:

• ToolExecutionErrorHandler
• AiServices.hallucinatedToolNameStrategy(Function)

Method Summary

Modifier and Type	Method	Description
ToolErrorHandlerResult	handle(Throwable error, ToolErrorContext context)	Handles an error that occurred during tool execution.

Method Details

handle

ToolErrorHandlerResult handle(Throwable error,
 ToolErrorContext context)

Handles an error that occurred during tool execution.

This method should either throw an exception or return a ToolErrorHandlerResult.text(String), which will be sent to the LLM as the result of the tool execution.

Parameters:

error - The actual error that occurred.

context - The context in which the error occurred.

Returns:

The result of error handling.