Spreadsheet Validated Execution

Direct Python Execution for Spreadsheet Tasks

When to Use This Skill

Use this skill for spreadsheet operations that require verified source data:

• Before processing: Verify data sources are accessible and contain expected data
• Reading or writing complex Excel files with multiple sheets
• Applying formulas, formatting, or data transformations
• Working with openpyxl, pandas, or similar libraries
• The operation involves multiple steps that could exceed agent step limits
• You need precise control over error handling and debugging
• Complex scripts benefit from file-based execution for better reliability

Critical: Data Source Validation First

Always validate data availability before attempting spreadsheet operations. This prevents wasted iterations on unavailable data.

Pre-Execution Validation Checklist

1. Verify source accessibility: Test connection to data URLs/files before building processing scripts
2. Confirm data format: Ensure source data matches expected structure (columns, sheets, file type)
3. Check data completeness: Validate required fields/rows are present
4. Identify fallback sources: Document alternative data sources if primary is unavailable

Validation Script Pattern

import sys
import os
from pathlib import Path

def validate_source(source_path, required_fields=None):
    """Validate data source before processing"""
    if not Path(source_path).exists():
        return False, f"Source file not found: {source_path}"
    
    try:
        # Check file is readable and non-empty
        if os.path.getsize(source_path) == 0:
            return False, "Source file is empty"
        
        if required_fields:
            # Validate structure using pandas
            import pandas as pd
            df = pd.read_excel(source_path, nrows=1)
            missing = set(required_fields) - set(df.columns)
            if missing:
                return False, f"Missing required columns: {missing}"
        
        return True, "Source validated"
    except Exception as e:
        return False, f"Validation error: {str(e)}"

# Usage
valid, message = validate_source('input.xlsx', ['ID', 'Date', 'Value'])
if not valid:
    print(f"ABORT: {message}", file=sys.stderr)
    sys.exit(1)
print(f"OK: {message}")

Handling Inaccessible Data Sources

When primary data sources are unavailable:

1. Report clearly: Document the specific error (SSL, timeout, file not found)
2. Attempt fallbacks: Check alternative sources in priority order:
   • Local cached copies of the data
   • Alternative API endpoints or URLs
   • Different file formats from the same source
   • Contact information for data provider
3. Graceful degradation: If partial data is available, document what's missing
4. Escalation protocol: For persistent failures, provide:
   • Exact error messages and timestamps
   • URLs/paths that were attempted
   • Workarounds already tried
   • Recommended next steps for human intervention

Example: Multi-Source Fallback Pattern

import sys
from pathlib import Path

sources = [
    'data/wells_current.xlsx',           # Primary: latest data
    'data/wells_backup.xlsx',            # Fallback 1: backup copy
    'data/wells_archive.xlsx',           # Fallback 2: archived version
    '/cached/wells_data.xlsx',           # Fallback 3: system cache
]

selected_source = None
for source in sources:
    if Path(source).exists():
        selected_source = source
        print(f"Using fallback source: {source}")
        break

if not selected_source:
    print("CRITICAL: No data sources available", file=sys.stderr)
    print("Attempted sources:", file=sys.stderr)
    for s in sources:
        print(f"  - {s}", file=sys.stderr)
    sys.exit(1)

# Proceed with selected_source

• Reading or writing complex Excel files with multiple sheets
• Applying formulas, formatting, or data transformations
• Working with openpyxl, pandas, or similar libraries
• The operation involves multiple steps that could exceed agent step limits
• You need precise control over error handling and debugging
• Complex scripts benefit from file-based execution for better reliability

Why Direct Execution?

The shell_agent tool can:

• Hit maximum step limits on complex multi-step operations
• Produce unexplained errors on formatting operations
• Fail on intricate spreadsheet reads/writes due to iterative parsing
• Fail to parse heredoc syntax correctly, causing 'unknown error' failures

Direct run_shell with Python is more reliable because it:

• Executes in a single step with no iteration limits
• Provides clearer, immediate error messages
• Handles complex operations without step constraints
• Gives full control over library imports and execution flow
• Writing scripts to .py files first avoids shell_agent parsing issues with heredocs

How to Use

Recommended Pattern: Write Script to File First

For complex multi-line scripts, especially when using shell_agent as executor:

# Step 1: Write the Python script to a file
cat > process_spreadsheet.py << 'EOF'
import openpyxl
from openpyxl import Workbook

# Your spreadsheet code here
wb = openpyxl.load_workbook('file.xlsx')
# ... operations ...
wb.save('output.xlsx')
print('Success')
EOF

# Step 2: Execute the script
python3 process_spreadsheet.py

Alternative Pattern: Inline Heredoc (Simple Scripts Only)

For short, simple scripts when NOT using shell_agent as the executor:

python3 << 'EOF'
import openpyxl
from openpyxl import Workbook

# Your spreadsheet code here
wb = openpyxl.load_workbook('file.xlsx')
# ... operations ...
wb.save('output.xlsx')
print('Success')
EOF

Example 1: Read and Transform Excel Data

Write to file first, then execute:

import pandas as pd

# Load data from specific sheet
df = pd.read_excel('input.xlsx', sheet_name='Revenue')

# Apply transformations
df['Net_Revenue'] = df['Gross_Revenue'] * (1 - df['Tax_Rate'])

# Save results
df.to_excel('output.xlsx', index=False, sheet_name='Processed')

Example 2: Multi-Sheet Operations with openpyxl

Write to file first, then execute:

from openpyxl import load_workbook

wb = load_workbook('tour_data.xlsx')

# Iterate through sheets
for sheet_name in wb.sheetnames:
    ws = wb[sheet_name]
    # Apply formatting or calculations
    for row in ws.iter_rows(min_row=2, max_col=5):
        # Process cells
        pass

wb.save('tour_data_processed.xlsx')

Example 3: Complex Formatting Operations

Write to file first, then execute:

from openpyxl import load_workbook
from openpyxl.styles import Font, PatternFill, Alignment

wb = load_workbook('report.xlsx')
ws = wb.active

# Apply header styling
header_fill = PatternFill(start_color='4472C4', fill_type='solid')
header_font = Font(bold=True, color='FFFFFF')

for cell in ws[1]:
    cell.fill = header_fill
    cell.font = header_font
    cell.alignment = Alignment(horizontal='center')

wb.save('report_formatted.xlsx')

Example 4: Error Handling Pattern

Write to file first, then execute:

import sys
from openpyxl import load_workbook

try:
    wb = load_workbook('data.xlsx')
    ws = wb.active
    
    # Your operations here
    value = ws['A1'].value
    
    wb.save('output.xlsx')
    print(f"Success: Processed {ws.max_row} rows")
    
except Exception as e:
    print(f"Error: {str(e)}", file=sys.stderr)
    sys.exit(1)

Best Practices

1. Prefer file-based execution for complex scripts: write to .py file first, then execute via run_shell
2. Import only needed libraries to reduce execution time
3. Print clear success/error messages for debugging
4. Save intermediate results for complex multi-step transformations
5. Test with small data before scaling to large spreadsheets
6. Use pandas for data manipulation and openpyxl for formatting when both are needed
7. Clean up temporary script files after execution if they won't be reused

When NOT to Use This Skill

• Simple single-cell reads/writes (use shell_agent or basic commands)
• Operations that require interactive user input
• Tasks where you need the agent to iteratively refine the approach

Common Libraries