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VBA Macro Capabilities

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Prerequisites

• Enable Trust access to the VBA project object model in Excel’s macro security settings.
• Ensure the workbook is saved as a macro-enabled format (.xlsm).
• If your organisation restricts code execution, coordinate with IT before enabling these tools.

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Available Tools

• vba_read
  • Parameters: workbookName, moduleType (Module, ClassModule, Worksheet, Workbook), moduleName.
  • Returns the full code contents and metadata such as module type and line count.
• vba_create
  • Creates a new module with supplied code and moduleName.
  • The Excel API backs up existing modules to %TEMP% before insertion for recovery.
• vba_update
  • Replaces the contents of an existing module. Accepts code and optional overwrite flags.
  • Generates a diff summary to help reviewers understand the change.

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Safe Usage Patterns

• Review generated code thoroughly before approving. Claude typically includes comments explaining what each routine does.
• Use vba_read to snapshot the current module before making changes so you can quickly revert if necessary.
• Combine VBA updates with natural language explanations in the chat to maintain an audit trail.

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Error Handling

• If trust settings are disabled, the tool returns an error instructing you to enable programmatic access.
• Invalid module names or syntax errors trigger descriptive exceptions, surfaced in the UI as tool:error.
• The API stores temporary backups when writing modules. If something goes wrong, you can restore from the backup path printed in the logs.

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Governance Recommendations

• Limit macro tools to experienced users or require secondary approval when Claude proposes VBA changes.
• Maintain version control by exporting modules after approval and storing them in your repository.
• Consider disabling the VBA tool set in environments where macros are prohibited; see Tool Selection for configuration guidance.