Function runTurn

packages/agent-core/src/loop/run-turn.ts:54–137

(input: RunTurnInput)

}

export async function runTurn(input: RunTurnInput): Promise<TurnResult> {
  const {
    turnId,
    signal,
    llm,
    buildMessages,
    buildMessagesStrict,
    dispatchEvent,
    tools,
    hooks,
    log,
    maxSteps,
    maxRetryAttempts,
    recordStepUsage: hostRecordStepUsage,
  } = input;
  let usage: TokenUsage = emptyUsage();
  let steps = 0;
  // Normal exits overwrite this with the completed step's stop reason.
  let stopReason: LoopTurnStopReason = 'end_turn';
  let activeStep: number | undefined;
  const recordStepUsage = async (
    stepUsage: TokenUsage,
  ): Promise<RecordStepUsageResult | void> => {
    usage = addUsage(usage, stepUsage);
    return hostRecordStepUsage?.(stepUsage);
  };

  try {
    while (true) {
      signal.throwIfAborted();

      if (maxSteps !== undefined && maxSteps > 0 && steps >= maxSteps) {
        throw createMaxStepsExceededError(maxSteps);
      }

      steps += 1;
      activeStep = steps;
      const stepResult = await executeLoopStep({
        turnId,
        signal,
        buildMessages,
        buildMessagesStrict,
        dispatchEvent,
        llm,
        tools,
        hooks,
        log,
        currentStep: steps,
        maxRetryAttempts,
        recordUsage: recordStepUsage,
      });
      activeStep = undefined;

      if (stepResult.stopReason === 'tool_use') {
        continue;
      }

      const terminalStopReason: LoopTerminalStepStopReason = stepResult.stopReason;