Method undo

packages/agent-core/src/agent/context/index.ts:181–239

(count: number)

  }

  undo(count: number): void {
    if (count <= 0) return;
    if (this._history.length === 0) return;

    this.agent.records.logRecord({ type: 'context.undo', count });

    let removedUserCount = 0;
    const removedMessages = new Set<ContextMessage>();
    let stoppedAtBoundary = false;
    for (let i = this._history.length - 1; i >= 0; i--) {
      const message = this._history[i];
      if (message === undefined) continue;
      if (message.origin?.kind === 'injection') continue;
      if (message.origin?.kind === 'compaction_summary') {
        stoppedAtBoundary = true;
        break;
      }

      removedMessages.add(message);
      this._history.splice(i, 1);
      this.agent.injection.onContextMessageRemoved(i);

      if (i < this.tokenCountCoveredMessageCount) {
        this.tokenCountCoveredMessageCount--;
        this._tokenCount -= estimateTokensForMessages([message]);
      }

      if (isRealUserInput(message)) {
        removedUserCount++;
        if (removedUserCount >= count) break;
      }
    }

    this.agent.replayBuilder.removeLastMessages(removedMessages);

    this.openSteps.clear();
    this.pendingToolResultIds.clear();
    this.deferredMessages = [];
    this.agent.microCompaction.reset(this._history.length);
    this.agent.emitStatusUpdated();

    if (
      !this.agent.records.restoring &&
      (stoppedAtBoundary || removedUserCount < count)
    ) {
      throw new KimiError(
        ErrorCodes.REQUEST_INVALID,
        formatUndoUnavailableMessage(count, removedUserCount, stoppedAtBoundary),
        {
          details: {
            reason: 'undo_limit',
            requestedCount: count,
            undoableCount: removedUserCount,
            stoppedAtCompaction: stoppedAtBoundary,
          },
        },
      );
    }