Method dispatchPendingFollowUp

src/node/services/agentSession.ts:5315–5473

* Dispatch the pending follow-up from a compaction summary message. * Called after compaction completes - the follow-up is stored on the summary * for crash safety. The user message persisted by sendMessage() serves as * proof of dispatch (no history rewrite needed).

(summaryMessageId?: string)

   * proof of dispatch (no history rewrite needed).
   */
  private async dispatchPendingFollowUp(summaryMessageId?: string): Promise<boolean> {
    if (this.disposed) {
      return false;
    }

    let summaryMessage: MuxMessage | undefined;
    if (summaryMessageId) {
      const historyResult = await this.historyService.getHistoryFromLatestBoundary(
        this.workspaceId
      );
      if (!historyResult.success) {
        throw new Error(
          `Failed to read history for targeted follow-up recovery: ${historyResult.error}`
        );
      }
      summaryMessage = historyResult.data.find((message) => message.id === summaryMessageId);
      if (!summaryMessage) {
        return false;
      }
    } else {
      // Read the last message from history — only need 1 message, avoid full-file read.
      // Startup recovery must retry on transient read failures, so bubble errors.
      const historyResult = await this.historyService.getLastMessages(this.workspaceId, 1);
      if (!historyResult.success) {
        const historyError =
          typeof historyResult.error === "string"
            ? historyResult.error
            : getErrorMessage(historyResult.error);
        throw new Error(`Failed to read history for startup follow-up recovery: ${historyError}`);
      }

      if (historyResult.data.length === 0) {
        return false;
      }
      summaryMessage = historyResult.data[0];
    }

    const lastMessage = summaryMessage;
    const muxMeta = lastMessage.metadata?.muxMetadata;

    // Check if it's a compaction summary with a pending follow-up
    if (!isCompactionSummaryMetadata(muxMeta) || !muxMeta.pendingFollowUp) {
      return false;
    }

    // Handle legacy formats: older persisted requests may have `mode` instead of `agentId`,
    // and `imageParts` instead of `fileParts`.
    const followUp = muxMeta.pendingFollowUp as typeof muxMeta.pendingFollowUp & {
      mode?: "exec" | "plan";
      imageParts?: FilePart[];
    };

    const hasQueuedMessages = this.hasPendingManualFollowUp();
    const hasActiveNonCompletingTurn = this.isBusy() && this.turnPhase !== TurnPhase.COMPLETING;
    if (
      followUp.dispatchOptions?.requireIdle === true &&
      (hasQueuedMessages || hasActiveNonCompletingTurn)
    ) {