ToolEmitter

Interface for emitting streaming responses during tool execution.

Tool methods can declare a ToolEmitter parameter to send intermediate progress updates and messages during execution. These streaming chunks are delivered to registered hooks via onActingChunk() events but are NOT sent to the LLM. Only the final return value of the tool method is sent to the LLM as the tool result.

Key Characteristics:

• ToolEmitter is auto-injected by the framework - no ToolParam annotation needed

• Emitted chunks go to hooks (for monitoring/logging), not to the LLM

• Useful for long-running tools to provide progress feedback

• Does not affect the tool schema visible to the LLM

Usage Example:

`@Tool(name = "long_task", description = "Execute a long running task")
public ToolResultBlock execute(
@ToolParam(name = "input") String input,
ToolEmitter emitter // Automatically injected by framework
) {
emitter.emit(ToolResultBlock.text("Starting task..."));

// Step 1
processStep1(input);
emitter.emit(ToolResultBlock.text("Step 1 completed"));

// Step 2
processStep2(input);
emitter.emit(ToolResultBlock.text("Step 2 completed"));

// Final result (this is what the LLM sees)
return ToolResultBlock.text("Task completed successfully");
}
`