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Error Recovery

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Cancel an In-Flight Request

• Press Esc or click Cancel Response to send stream:cancel.
• The backend aborts the Claude request via AbortController, logs a cancellation span in Langfuse, and notifies the UI with stream:cancelled.
• Continue the conversation with a corrected prompt or restart if needed.

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Revert Applied Tools

• For each approved tool, select Revert. The backend executes revertToolChangesForWorkbookFromToolIdOnwards, restoring the workbook using stored inputDataRevert payloads.
• Conversation history records the revert action so Claude acknowledges that the previous results are no longer valid.
• You can reapply the same tool later using Apply if you change your mind.

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Handle Tool Failures

• When a tool throws ToolExecutionError, the UI shows the error message and stack trace (if available).
• Suggested workflow:
  1. Review the error details (range mismatch, protected sheet, etc.).
  2. Adjust the prompt or workbook state.
  3. Ask Claude to retry or propose an alternative.
• The backend also updates the conversation with the failure context to inform future reasoning.

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Restart a Conversation

• Click Restart Chat to clear state. This sends chat:restart, aborts any active request, and wipes conversation + tool history for the current workbook.
• Use this after a major workbook change or when the conversation drifts off-topic.

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Recover from Backend Crashes

• If the Deno server crashes, close Excel to terminate the hosting process, then reopen Excel. Ports and state are reinitialised automatically.
• Check %LOCALAPPDATA%\X21\X21-deno\Logs for crash details and share them with the engineering team.

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Restore from Version Control

• If a workbook becomes corrupted, revert to the last known-good version from your source control or backup solution.
• For ClickOnce deployments, re-run the installer (setup.exe) to repair the add-in.