Function executeLoopStep

packages/agent-core/src/loop/turn-step.ts:48–227

(deps: ExecuteLoopStepDeps)

}

export async function executeLoopStep(deps: ExecuteLoopStepDeps): Promise<{
  readonly usage: TokenUsage;
  readonly stopReason: LoopStepStopReason;
}> {
  const {
    turnId,
    signal,
    buildMessages,
    buildMessagesStrict,
    dispatchEvent,
    llm,
    tools,
    hooks,
    log,
    currentStep,
    maxRetryAttempts,
    recordUsage,
  } = deps;

  if (hooks?.beforeStep !== undefined) {
    const beforeStep = await hooks.beforeStep({
      turnId,
      stepNumber: currentStep,
      signal,
      llm,
    });
    if (beforeStep?.block === true) {
      throw new Error(beforeStep.reason ?? `Step ${String(currentStep)} was blocked`);
    }
  }

  signal.throwIfAborted();

  const messages = await buildMessages();
  signal.throwIfAborted();

  const stepUuid = randomUUID();

  const step: ToolCallStepContext = {
    tools,
    hooks,
    log,
    dispatchEvent,
    llm,
    signal,
    turnId,
    currentStep,
    stepUuid,
  };

  await dispatchEvent({
    type: 'step.begin',
    uuid: stepUuid,
    turnId,
    step: currentStep,
  });

  const chatParams: LLMChatParams = {