Excel VBA Modifier Skill

Safe VBA code modification with xlwings

Overview

Automates VBA code modifications while ensuring safety:

• Verify Trust Center allows programmatic VBA access
• Read VBA module code from .xlsm files
• Write/modify VBA module code safely
• Run test macros to validate changes
• Automatic backup before modifications

When to Use

• Modifying VBA code: Safe xlwings-based editing
• Testing macro changes: Run macros to validate
• Debugging VBA: Read module code without manual editing
• Batch updates: Apply changes to multiple macros
• Following safety rules: Automatic backup and validation

Usage

# Check Trust Center permissions
conda run -n excel python script/modify_vba.py check-trust perturb_inform.xlsm

# Read a VBA module
conda run -n excel python script/modify_vba.py read perturb_inform.xlsm Module2

# Write/modify a VBA module (from file)
conda run -n excel python script/modify_vba.py write perturb_inform.xlsm Module2 new_code.vba

# Run a macro to test
conda run -n excel python script/modify_vba.py run perturb_inform.xlsm BuildMetaSummary

Features

Trust Center Checking

conda run -n excel python script/modify_vba.py check-trust file.xlsm

Output:

✓ Trust Center check passed
✓ VBA project access allowed

Reading VBA Code

conda run -n excel python script/modify_vba.py read file.xlsm Module2

Outputs module code to console (can redirect to file).

Writing VBA Code

# Write from file
conda run -n excel python script/modify_vba.py write file.xlsm Module2 new_code.vba

# Automatically creates backup first
# Then replaces module with new code

Running Macros

# Test macro after modification
conda run -n excel python script/modify_vba.py run file.xlsm BuildMetaSummary

# With arguments (if applicable)
conda run -n excel python script/modify_vba.py run file.xlsm Sub1 arg1 arg2

Safety Features

✓ Automatic backup before modifications ✓ Trust Center validation ✓ Test macro execution ✓ Error handling and rollback ✓ Windows only (COM access)

Integration with Other Skills

• excel-backup-manager: Auto-backup before writes
• excel-inspector: Understand VBA structure
• excel-na-utils: Helper functions for VBA code

Requirements

• OS: Windows only (xlwings COM access)
• Package: xlwings
• Trust Center: Must allow programmatic VBA access
• Excel: Installed and configured

Error Handling

Error	Solution
Trust Center blocked	Enable in Excel: File > Options > Trust Center
Module not found	Use excel-inspector to list modules
Write failed	Check file isn't open in Excel
Macro failed	Check syntax in new VBA code

Workflow

User request
    ↓
Check Trust Center
    ↓
Create backup (via excel-backup-manager)
    ↓
Read current module
    ↓
Write new module
    ↓
Run test macro
    ↓
Report success/failure

Files

• vba_modifier.py: Core VBA modification logic
• trust_center_checker.py: Trust Center validation
• CLI: script/modify_vba.py