Excel Builder

Build .xlsx files with formulas, merged cells, data validation, conditional formatting, pivot tables, and charts. Use when creating Excel spreadsheets, finan...

Security Scan

This instruction-only skill is internally coherent: its requirements and runtime instructions align with building .xlsx files and it does not request unrelated credentials, installs, or system access.

Purpose & Capability

The name/description (Excel/.xlsx creation with formulas, charts, validations) matches the SKILL.md content. All recommended libraries (openpyxl, xlsxwriter) are appropriate for the stated purpose.

Instruction Scope

The instructions stay on-topic: designing sheets, writing data, adding formulas/formatting, creating charts, and saving/verifying files. They do not instruct reading unrelated system files, transmitting data to external endpoints, or accessing credentials.

Install Mechanism

There is no install spec (instruction-only), which is low-risk. The SKILL.md suggests using `pip install` if libraries are missing — this implies network access to PyPI when run and will install packages into the agent environment, but the suggestion itself is consistent with the skill's needs.

Credentials

No environment variables, credentials, or config paths are requested. The skill's operations (file write/read, package installs) are proportionate to generating Excel files.

Persistence & Privilege

The skill is not marked `always:true` and does not request elevated or persistent system-wide changes. It writes output files (normal for this purpose) and may install Python packages into the runtime environment, which is standard behavior for a code-generating skill.

Assessment

This skill appears to do what it claims: programmatically build .xlsx files using openpyxl/xlsxwriter. Before installing or invoking it, note that (1) the agent may run pip to install libraries from PyPI (network activity and changes to the runtime environment), (2) it will write files to disk — verify output paths to avoid overwriting important files, and (3) because it can be invoked by the agent, review any generated code or commands before allowing autonomous runs. If you need stricter controls, run it in a sandboxed environment or restrict network/package installation.

Builds structured .xlsx files programmatically using Python libraries (openpyxl or xlsxwriter).

When to Use This Skill

• Creating Excel spreadsheets with formulas and calculated fields
• Building financial tables, budgets, or invoices
• Generating data entry forms with validation and dropdowns
• Producing reports with charts (bar, line, pie, scatter)
• Exporting structured data with conditional formatting or color coding
• Building pivot-ready data tables

Core Workflow

1. Choose library — Use openpyxl for reading/modifying existing files; use xlsxwriter for new write-only files with rich charts
2. Design structure — Define sheets, columns, headers, and data rows before writing
3. Write data — Populate cells row by row; apply number formats ("#,##0.00", "YYYY-MM-DD")
4. Add formulas — Use Excel formula strings: =SUM(B2:B100), =IF(A2>0, "Yes", "No")
5. Format — Apply styles: bold headers, column widths, merged cells, fill colors, borders
6. Validate — Add data validation (dropdown lists, numeric ranges) where applicable
7. Charts — Add charts referencing data ranges; set titles and axis labels
8. Save and verify — Save to output path; confirm file exists and is non-zero bytes

Key Patterns

openpyxl (read/write existing)

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

wb = Workbook()
ws = wb.active
ws.title = "Report"
ws["A1"] = "Revenue"
ws["A1"].font = Font(bold=True, size=12)
ws.column_dimensions["A"].width = 20
wb.save("output.xlsx")

xlsxwriter (new files with charts)

import xlsxwriter
wb = xlsxwriter.Workbook("output.xlsx")
ws = wb.add_worksheet("Summary")
bold = wb.add_format({"bold": True, "bg_color": "#4472C4", "font_color": "white"})
ws.write("A1", "Month", bold)
chart = wb.add_chart({"type": "column"})
chart.add_series({"values": "=Summary!$B$2:$B$13", "name": "Revenue"})
ws.insert_chart("D2", chart)
wb.close()

Error Handling

• If openpyxl not installed: pip install openpyxl
• If xlsxwriter not installed: pip install xlsxwriter
• Always wrap wb.save() in try/except; report path conflicts
• Verify output with os.path.getsize(path) > 0 before returning

Output

Return the absolute path to the saved .xlsx file. If generating multiple sheets, list each sheet name and row count in a brief summary.