Spreadsheet toolkit (.xlsx/.csv). Create/edit with formulas/formatting, analyze data, visualization, recalculate formulas, for spreadsheet processing and analysis.
SkillScore88Maintained
Automatic
◆Finance & Accounting pack
Last verified 8/21/2026
What it changes
Passed 20 of 23 test cases with the skill, and 14 of 23 without it.
Without skill63%
With skill88%
Checks it passed that the model alone missed
The documentation text begins with 'Source:'.
The cell number_format property is set to '0.0x'.
The command specifies running python recalc.py model.xlsx.
and 4 more in the full report
7 fixed14 passed either way2 still failing1 broke
Pass-rate lift
+25 pp
Tokens
+98%
Agent turns
0%
Response time
-36%
Model gemini-3.6-flashMeasured 8/21/2026v121 of 24 cases passed with skill · 23 comparable
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 7 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 7
Prompt
In an openpyxl financial summary table, cell E10 contains an EV/EBITDA valuation multiple of 8.5. What number format string should be applied to cell E10?
What was checked, without and with the skill
Checked
Without skill
With skill
The cell number_format property is set to '0.0x'.
Missed
Passed
case-13 · gemini-3.6-flash · 8/21/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md283 linessingle file
Requirements for Outputs
All Excel files
Zero Formula Errors
Every Excel model MUST be delivered with ZERO formula errors (#REF!, #DIV/0!, #VALUE!, #N/A, #NAME?)
Comprehensive spreadsheet creation, editing, and analysis with support for formulas, formatting, data analysis, and visualization. When Claude needs to work with spreadsheets (.xlsx, .xlsm, .csv, .tsv, etc) for: (1) Creating new spreadsheets with formulas and formatting, (2) Reading or analyzing data, (3) Modify existing spreadsheets while preserving formulas, (4) Data analysis and visualization in spreadsheets, or (5) Recalculating formulas