Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add PracticalSwan/agent-skills --skill spreadsheet-formula-helpergit clone --depth 1 https://github.com/PracticalSwan/agent-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/practicalswan/agent-skills/spreadsheet-formula-helper)<a href="https://agentmods.dev/skills/practicalswan/agent-skills/spreadsheet-formula-helper"><img src="https://agentmods.dev/badge/skills/practicalswan/agent-skills/spreadsheet-formula-helper.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00042 | $0.00940 |
| Opus 5 | $0.00021 | $0.00470 |
| Sonnet 5 | $0.00008 | $0.00188 |
| Haiku 4.5 | $0.00004 | $0.00094 |
Grade A, and why
spreadsheet-formula-helper scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured today.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 82 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Spreadsheet Formula Helper
Produce reliable spreadsheet formulas with explanations.
- Leverage native parallel subagent dispatch and 200k+ context windows where available.
Inputs to gather
- Platform (Excel/Sheets), locale (comma vs. semicolon separators), sample data layout (headers, ranges), expected outputs, and constraints (volatile functions allowed?).
- Provide small example rows and the desired result for them.
Workflow
- Restate the problem with explicit ranges and sheet names; propose a minimal sample to verify.
- Draft formula(s); when dynamic arrays are available, prefer them over copy-down formulas.
- Explain how it works and where to place it; include named ranges if helpful.
- Edge cases: blank rows, mixed types, timezone/date quirks, duplicates; offer guardrails (e.g.,
IFERROR,LET,LAMBDA). - Variants: if porting between Excel and Sheets, provide both versions.
Output
- Primary formula, short explanation, and a 2-3 row worked example showing inputs to outputs.
- Optional: quick troubleshooting checklist for common errors.
MCP Fallback – Native Automation
When MCP is unavailable, use native automation: local spreadsheet formulas, openpyxl for workbook inspection, CSV fixtures for examples, and manual recalculation notes for functions the local engine cannot evaluate. Preserve locale separators, absolute references, dynamic arrays, and Excel-vs-Sheets differences before claiming success.
Cross-Client Portability
This skill is written to stay usable across GitHub Copilot, Claude Code, and Codex.
- GitHub Copilot: keep the folder in a Copilot-visible skill path or wrap the workflow in project instructions when folder discovery is unavailable.
- Claude Code: keep the folder in a local skills directory or a compatible plugin source.
- Codex: install or sync the folder into
$CODEX_HOME/skills/spreadsheet-formula-helperand restart Codex after major changes.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- today Changed · -1 lines 017d829685cb
- 2d ago Changed dbbb3bf03765
- 4d ago First seen · 83 lines · 42 tokens per session scan A a73f1c1bbc35
spreadsheet-formula-helper is a skill published in the GitHub repository PracticalSwan/agent-skills (13 stars, last pushed today), licensed MIT. It adds 42 tokens to every session and 940 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
Other skills, from other repositories
excel-automation
This skill enables advanced Excel automation using xlwings - a library that can interact with live Excel instances. Unlike openpyxl (file-only), xlwings can control Excel in real-time, execute VBA, update dashboards, and automate complex workflows.
guides
This guide helps Claude (and other AI assistants) use ServalSheets MCP server effectively.
gws-sheets
Google Sheets: Read and write spreadsheets.
gws-sheets-append
Google Sheets: Append a row to a spreadsheet.
gws-sheets-read
Google Sheets: Read values from a spreadsheet.
recipe-create-expense-tracker
Set up a Google Sheets spreadsheet for tracking expenses with headers and initial entries.